{"id":2127,"date":"2024-12-19T17:55:26","date_gmt":"2024-12-19T09:55:26","guid":{"rendered":"http:\/\/blog.xtaa.cn\/?p=2127"},"modified":"2024-12-20T11:57:17","modified_gmt":"2024-12-20T03:57:17","slug":"javascript%e5%86%8d%e5%a4%8d%e4%b9%a0","status":"publish","type":"post","link":"http:\/\/blog.xtaa.cn\/index.php\/2024\/12\/19\/javascript%e5%86%8d%e5%a4%8d%e4%b9%a0\/","title":{"rendered":"JavaScript\u518d\u590d\u4e60"},"content":{"rendered":"\n

https:\/\/liaoxuefeng.com\/books\/javascript\/introduction\/index.html<\/a>\u6458\u81ea<\/p>\n\n\n\n

\u4e0b\u9762\u7684\u4e00\u884c\u4ee3\u7801\u5305\u542b\u4e24\u4e2a\u8bed\u53e5\uff0c\u6bcf\u4e2a\u8bed\u53e5\u7528;<\/code>\u8868\u793a\u8bed\u53e5\u7ed3\u675f<\/p>\n\n\n\n

var x = 1; var y = 2; \/\/ \u5b9a\u4e49\u4e86\u4e24\u4e2a\u53d8\u91cf\uff0c\u4e0d\u5efa\u8bae\u4e00\u884c\u5199\u591a\u4e2a\u8bed\u53e5!\n<\/code><\/pre>\n\n\n\n
\u7528\u7b49\u53f7=\u5bf9\u53d8\u91cf\u8fdb\u884c\u8d4b\u503c\u3002\u53ef\u4ee5\u628a\u4efb\u610f\u6570\u636e\u7c7b\u578b\u8d4b\u503c\u7ed9\u53d8\u91cf\uff0c\u540c\u4e00\u4e2a\u53d8\u91cf\u53ef\u4ee5\u53cd\u590d\u8d4b\u503c\uff0c\u800c\u4e14\u53ef\u4ee5\u662f\u4e0d\u540c\u7c7b\u578b\u7684\u53d8\u91cf\uff0c\u4f46\u662f\u8981\u6ce8\u610f\u53ea\u80fd\u7528var\u7533\u660e\u4e00\u6b21\uff0c\u4f8b\u5982\uff1a\n\nvar a = 123; \/\/ a\u7684\u503c\u662f\u6574\u6570123\na = 'ABC'; \/\/ a\u53d8\u4e3a\u5b57\u7b26\u4e32\n\u8fd9\u79cd\u53d8\u91cf\u672c\u8eab\u7c7b\u578b\u4e0d\u56fa\u5b9a\u7684\u8bed\u8a00\u79f0\u4e4b\u4e3a\u52a8\u6001\u8bed\u8a00<\/code><\/pre>\n\n\n\n
\u5982\u679c\u4e00\u4e2a\u53d8\u91cf\u6ca1\u6709\u901a\u8fc7var<\/code>\u7533\u660e\u5c31\u88ab\u4f7f\u7528\uff0c\u90a3\u4e48\u8be5\u53d8\u91cf\u5c31\u81ea\u52a8\u88ab\u7533\u660e\u4e3a\u5168\u5c40\u53d8\u91cf\uff1a<\/p>\n\n\n\n
i = 10; \/\/ i\u73b0\u5728\u662f\u5168\u5c40\u53d8\u91cf\n<\/code><\/pre>\n\n\n\n
\u5728\u540c\u4e00\u4e2a\u9875\u9762\u7684\u4e0d\u540c\u7684JavaScript\u6587\u4ef6\u4e2d\uff0c\u5982\u679c\u90fd\u4e0d\u7528var<\/code>\u7533\u660e\uff0c\u6070\u597d\u90fd\u4f7f\u7528\u4e86\u53d8\u91cfi<\/code>\uff0c\u5c06\u9020\u6210\u53d8\u91cfi<\/code>\u4e92\u76f8\u5f71\u54cd\uff0c\u4ea7\u751f\u96be\u4ee5\u8c03\u8bd5\u7684\u9519\u8bef\u7ed3\u679c\u3002\u8fd9\u662f\u8981\u907f\u514d\u7684\uff0c\u53ef\u4ee5\u5728JavaScript\u4ee3\u7801\u7684\u7b2c\u4e00\u884c\u5199\u4e0a\uff1a’use strict’;\u5f3a\u5236\u8981\u6c42\u901a\u8fc7var<\/code>\u7533\u660e\u53d8\u91cf<\/p>\n\n\n\n
const<\/code>\u6765\u5b9a\u4e49\u5e38\u91cf\uff0c\u6bd4\u5982const PI = 3.1415926\u8981\u6c42\u6570\u503c\u4e00\u5b9a\u540e\u9762\u4e0d\u80fd\u6539\uff0c\u53ef\u4ee5\u7528\u8fd9\u4e2a\u5b9a\u4e49<\/p>\n\n\n\n
\u8bed\u53e5\u5757\u662f\u4e00\u7ec4\u8bed\u53e5\u7684\u96c6\u5408\uff0c\u4f8b\u5982\uff0c\u4e0b\u9762\u7684\u4ee3\u7801\u5148\u505a\u4e86\u4e00\u4e2a\u5224\u65ad\uff0c\u5982\u679c\u5224\u65ad\u6210\u7acb\uff0c\u5c06\u6267\u884c{...}<\/code>\u4e2d\u7684\u6240\u6709\u8bed\u53e5\uff1a<\/p>\n\n\n\n
if (2 > 1) {\n    x = 1;\n    y = 2;\n    z = 3;\n}\n<\/code><\/pre>\n\n\n\n
\u6ce8\u610f\u82b1\u62ec\u53f7{...}<\/code>\u5185\u7684\u8bed\u53e5\u5177\u6709\u7f29\u8fdb\uff0c\u901a\u5e38\u662f4\u4e2a\u7a7a\u683c\u3002\u7f29\u8fdb\u4e0d\u662fJavaScript\u8bed\u6cd5\u8981\u6c42\u5fc5\u987b\u7684<\/p>\n\n\n\n
\u4ee5\/\/<\/code>\u5f00\u5934\u76f4\u5230\u884c\u672b\u7684\u5b57\u7b26\u88ab\u89c6\u4e3a\u884c\u6ce8\u91ca\uff0c    \/*...*\/<\/code>\u628a\u591a\u884c\u5b57\u7b26\u5305\u88f9\u8d77\u6765<\/p>\n\n\n\n
<\/p>\n\n\n\n
JavaScript\u4e0d\u533a\u5206\u6574\u6570\u548c\u6d6e\u70b9\u6570\uff0c\u7edf\u4e00\u7528Number\u8868\u793a\uff0c\u4ee5\u4e0b\u90fd\u662f\u5408\u6cd5\u7684Number\u7c7b\u578b\uff1a<\/p>\n\n\n\n
123; \/\/ \u6574\u6570123\n0.456; \/\/ \u6d6e\u70b9\u65700.456\n1.2345e3; \/\/ \u79d1\u5b66\u8ba1\u6570\u6cd5\u8868\u793a1.2345x1000\uff0c\u7b49\u540c\u4e8e1234.5\n-99; \/\/ \u8d1f\u6570\nNaN; \/\/ NaN\u8868\u793aNot a Number\uff0c\u5f53\u65e0\u6cd5\u8ba1\u7b97\u7ed3\u679c\u65f6\u7528NaN\u8868\u793a\nInfinity; \/\/ Infinity\u8868\u793a\u65e0\u9650\u5927\uff0c\u5f53\u6570\u503c\u8d85\u8fc7\u4e86JavaScript\u7684Number\u6240\u80fd\u8868\u793a\u7684\u6700\u5927\u503c\u65f6\uff0c\u5c31\u8868\u793a\u4e3aInfinity\n<\/code><\/pre>\n\n\n\n
\u8ba1\u7b97\u673a\u7531\u4e8e\u4f7f\u7528\u4e8c\u8fdb\u5236\uff0c\u6240\u4ee5\uff0c\u6709\u65f6\u5019\u7528\u5341\u516d\u8fdb\u5236\u8868\u793a\u6574\u6570\u6bd4\u8f83\u65b9\u4fbf\uff0c\u5341\u516d\u8fdb\u5236\u75280x\u524d\u7f00\u548c0-9\uff0ca-f\u8868\u793a\uff0c\u4f8b\u5982\uff1a0xff00<\/code>\uff0c0xa5b4c3d2<\/code>\uff0c\u7b49\u7b49\uff0c\u5b83\u4eec\u548c\u5341\u8fdb\u5236\u8868\u793a\u7684\u6570\u503c\u5b8c\u5168\u4e00\u6837\u3002<\/p>\n\n\n\n
Number\u53ef\u4ee5\u76f4\u63a5\u505a\u56db\u5219\u8fd0\u7b97\uff0c\u89c4\u5219\u548c\u6570\u5b66\u4e00\u81f4\uff1a<\/p>\n\n\n\n
1 + 2; \/\/ 3\n(1 + 2) * 5 \/ 2; \/\/ 7.5\n2 \/ 0; \/\/ Infinity\n0 \/ 0; \/\/ NaN\n10 % 3; \/\/ 1\n10.5 % 3; \/\/ 1.5\n<\/code><\/pre>\n\n\n\n
\u6ce8\u610f%<\/code>\u662f\u6c42\u4f59\u8fd0\u7b97\u3002<\/p>\n\n\n\n
\u8981\u6ce8\u610f\uff0cJavaScript\u7684Number\u4e0d\u533a\u5206\u6574\u6570\u548c\u6d6e\u70b9\u6570\uff0c\u4e5f\u5c31\u662f\u8bf4\uff0c12.00 === 12<\/code>\u3002\uff08\u5728\u5927\u591a\u6570\u5176\u4ed6\u8bed\u8a00\u4e2d\uff0c\u6574\u6570\u548c\u6d6e\u70b9\u6570\u4e0d\u80fd\u76f4\u63a5\u6bd4\u8f83\uff09\u5e76\u4e14\uff0cJavaScript\u7684\u6574\u6570\u6700\u5927\u8303\u56f4\u4e0d\u662f\u00b1263<\/sup>\uff0c\u800c\u662f\u00b1253<\/sup>\uff0c\u56e0\u6b64\uff0c\u8d85\u8fc7253<\/sup>\u7684\u6574\u6570\u5c31\u53ef\u80fd\u65e0\u6cd5\u7cbe\u786e\u8868\u793a\uff1a\uff0c\u5982\u679c\u4e00\u4e32\u5b57\u7b26\u5f88\u957f\u4e14\u4e0d\u662f\u8ba1\u7b97\u5219\u5c3d\u91cf\u8981\u628a\u4ed6\u53d8\u6210\u5b57\u7b26\u4e32\uff0c\u5426\u5219\u4f1a\u628a\u540e\u9762\u622a\u53bb\u5f71\u54cd\u7ed3\u679c<\/p>\n\n\n\n
\/\/ \u8ba1\u7b97\u5706\u9762\u79ef:
var r = 123.456;
var s = 3.14 * r * r;
console.log(s); \/\/ 47857.94555904001<\/p>\n\n\n\n
\u5b57\u7b26\u4e32\u662f\u4ee5\u5355\u5f15\u53f7’\u6216\u53cc\u5f15\u53f7”\u62ec\u8d77\u6765\u7684\u4efb\u610f\u6587\u672c\uff0c\u6bd4\u5982'abc'<\/code>\uff0c\"xyz\"<\/code>\u7b49\u7b49\u3002\u8bf7\u6ce8\u610f\uff0c''<\/code>\u6216\"\"<\/code>\u672c\u8eab\u53ea\u662f\u4e00\u79cd\u8868\u793a\u65b9\u5f0f\uff0c\u4e0d\u662f\u5b57\u7b26\u4e32\u7684\u4e00\u90e8\u5206\uff0c\u56e0\u6b64\uff0c\u5b57\u7b26\u4e32'abc'<\/code>\u53ea\u6709a<\/code>\uff0cb<\/code>\uff0cc<\/code>\u8fd93\u4e2a\u5b57\u7b26<\/p>\n\n\n\n
<\/p>\n\n\n\n
&&<\/code>\u8fd0\u7b97\u662f\u4e0e\u8fd0\u7b97\uff0c\u53ea\u6709\u6240\u6709\u90fd\u4e3atrue<\/code>\uff0c&&<\/code>\u8fd0\u7b97\u7ed3\u679c\u624d\u662ftrue<\/code>\uff1a<\/p>\n\n\n\n
true && true; \/\/ \u8fd9\u4e2a&&\u8bed\u53e5\u8ba1\u7b97\u7ed3\u679c\u4e3atrue\ntrue && false; \/\/ \u8fd9\u4e2a&&\u8bed\u53e5\u8ba1\u7b97\u7ed3\u679c\u4e3afalse\nfalse && true && false; \/\/ \u8fd9\u4e2a&&\u8bed\u53e5\u8ba1\u7b97\u7ed3\u679c\u4e3afalse\n<\/code><\/pre>\n\n\n\n
||<\/code>\u8fd0\u7b97\u662f\u6216\u8fd0\u7b97\uff0c\u53ea\u8981\u5176\u4e2d\u6709\u4e00\u4e2a\u4e3atrue<\/code>\uff0c||<\/code>\u8fd0\u7b97\u7ed3\u679c\u5c31\u662ftrue<\/code>\uff1a<\/p>\n\n\n\n
false || false; \/\/ \u8fd9\u4e2a||\u8bed\u53e5\u8ba1\u7b97\u7ed3\u679c\u4e3afalse\ntrue || false; \/\/ \u8fd9\u4e2a||\u8bed\u53e5\u8ba1\u7b97\u7ed3\u679c\u4e3atrue\nfalse || true || false; \/\/ \u8fd9\u4e2a||\u8bed\u53e5\u8ba1\u7b97\u7ed3\u679c\u4e3atrue\n<\/code><\/pre>\n\n\n\n
!<\/code>\u8fd0\u7b97\u662f\u975e\u8fd0\u7b97\uff0c\u5b83\u662f\u4e00\u4e2a\u5355\u76ee\u8fd0\u7b97\u7b26\uff0c\u628atrue<\/code>\u53d8\u6210false<\/code>\uff0cfalse<\/code>\u53d8\u6210true<\/code>\uff1a<\/p>\n\n\n\n
! true; \/\/ \u7ed3\u679c\u4e3afalse\n\n\u5b9e\u9645\u4e0a\uff0cJavaScript\u5141\u8bb8\u5bf9\u4efb\u610f\u6570\u636e\u7c7b\u578b\u505a\u6bd4\u8f83\uff1a\n\nfalse == 0; \/\/ true\nfalse === 0; \/\/ false\n\u8981\u7279\u522b\u6ce8\u610f\u76f8\u7b49\u8fd0\u7b97\u7b26==\u3002JavaScript\u5728\u8bbe\u8ba1\u65f6\uff0c\u6709\u4e24\u79cd\u6bd4\u8f83\u8fd0\u7b97\u7b26\uff1a\n\n\u7b2c\u4e00\u79cd\u662f==\u6bd4\u8f83\uff0c\u5b83\u4f1a\u81ea\u52a8\u8f6c\u6362\u6570\u636e\u7c7b\u578b\u518d\u6bd4\u8f83\uff0c\u5f88\u591a\u65f6\u5019\uff0c\u4f1a\u5f97\u5230\u975e\u5e38\u8be1\u5f02\u7684\u7ed3\u679c\uff1b\n\n\u7b2c\u4e8c\u79cd\u662f===\u6bd4\u8f83\uff0c\u5b83\u4e0d\u4f1a\u81ea\u52a8\u8f6c\u6362\u6570\u636e\u7c7b\u578b\uff0c\u5982\u679c\u6570\u636e\u7c7b\u578b\u4e0d\u4e00\u81f4\uff0c\u8fd4\u56defalse\uff0c\u5982\u679c\u4e00\u81f4\uff0c\u518d\u6bd4\u8f83\u3002\n\n\u7531\u4e8eJavaScript\u8fd9\u4e2a\u8bbe\u8ba1\u7f3a\u9677\uff0c\u4e0d\u8981\u4f7f\u7528==\u6bd4\u8f83\uff0c\u59cb\u7ec8\u575a\u6301\u4f7f\u7528===\u6bd4\u8f83\u3002\n\n\u53e6\u4e00\u4e2a\u4f8b\u5916\u662fNaN\u8fd9\u4e2a\u7279\u6b8a\u7684Number\u4e0e\u6240\u6709\u5176\u4ed6\u503c\u90fd\u4e0d\u76f8\u7b49\uff0c\u5305\u62ec\u5b83\u81ea\u5df1\uff1a\n\nNaN === NaN; \/\/ false\n\u552f\u4e00\u80fd\u5224\u65adNaN\u7684\u65b9\u6cd5\u662f\u901a\u8fc7isNaN()\u51fd\u6570\uff1a\n\nisNaN(NaN); \/\/ true\n\u6700\u540e\u8981\u6ce8\u610f\u6d6e\u70b9\u6570\u7684\u76f8\u7b49\u6bd4\u8f83\uff1a\n\n1 \/ 3 === (1 - 2 \/ 3); \/\/ false\n\u8fd9\u4e0d\u662fJavaScript\u7684\u8bbe\u8ba1\u7f3a\u9677\u3002\u6d6e\u70b9\u6570\u5728\u8fd0\u7b97\u8fc7\u7a0b\u4e2d\u4f1a\u4ea7\u751f\u8bef\u5dee\uff0c\u56e0\u4e3a\u8ba1\u7b97\u673a\u65e0\u6cd5\u7cbe\u786e\u8868\u793a\u65e0\u9650\u5faa\u73af\u5c0f\u6570\u3002\u8981\u6bd4\u8f83\u4e24\u4e2a\u6d6e\u70b9\u6570\u662f\u5426\u76f8\u7b49\uff0c\u53ea\u80fd\u8ba1\u7b97\u5b83\u4eec\u4e4b\u5dee\u7684\u7edd\u5bf9\u503c\uff0c\u770b\u662f\u5426\u5c0f\u4e8e\u67d0\u4e2a\u9608\u503c\uff1a\n\nMath.abs(1 \/ 3 - (1 - 2 \/ 3)) < 0.0000001; \/\/ true\n\nnull\u548cundefined\nnull\u8868\u793a\u4e00\u4e2a\u201c\u7a7a\u201d\u7684\u503c\uff0c\u5b83\u548c0\u4ee5\u53ca\u7a7a\u5b57\u7b26\u4e32''\u4e0d\u540c\uff0c0\u662f\u4e00\u4e2a\u6570\u503c\uff0c''\u8868\u793a\u957f\u5ea6\u4e3a0\u7684\u5b57\u7b26\u4e32\uff0c\u800cnull\u8868\u793a\u201c\u7a7a\u201d\u3002\n\n\u5728\u5176\u4ed6\u8bed\u8a00\u4e2d\uff0c\u4e5f\u6709\u7c7b\u4f3cJavaScript\u7684null\u7684\u8868\u793a\uff0c\u4f8b\u5982Java\u4e5f\u7528null\uff0cSwift\u7528nil\uff0cPython\u7528None\u8868\u793a\u3002\u4f46\u662f\uff0c\u5728JavaScript\u4e2d\uff0c\u8fd8\u6709\u4e00\u4e2a\u548cnull\u7c7b\u4f3c\u7684undefined\uff0c\u5b83\u8868\u793a\u201c\u672a\u5b9a\u4e49\u201d\u3002\n\nJavaScript\u7684\u8bbe\u8ba1\u8005\u5e0c\u671b\u7528null\u8868\u793a\u4e00\u4e2a\u7a7a\u7684\u503c\uff0c\u800cundefined\u8868\u793a\u503c\u672a\u5b9a\u4e49\u3002\u4e8b\u5b9e\u8bc1\u660e\uff0c\u8fd9\u5e76\u6ca1\u6709\u4ec0\u4e48\u5375\u7528\uff0c\u533a\u5206\u4e24\u8005\u7684\u610f\u4e49\u4e0d\u5927\u3002\u5927\u591a\u6570\u60c5\u51b5\u4e0b\uff0c\u6211\u4eec\u90fd\u5e94\u8be5\u7528null\u3002undefined\u4ec5\u4ec5\u5728\u5224\u65ad\u51fd\u6570\u53c2\u6570\u662f\u5426\u4f20\u9012\u7684\u60c5\u51b5\u4e0b\u6709\u7528\n\n\u6570\u7ec4\u662f\u4e00\u7ec4\u6309\u987a\u5e8f\u6392\u5217\u7684\u96c6\u5408\uff0c\u96c6\u5408\u7684\u6bcf\u4e2a\u503c\u79f0\u4e3a\u5143\u7d20\u3002JavaScript\u7684\u6570\u7ec4\u53ef\u4ee5\u5305\u62ec\u4efb\u610f\u6570\u636e\u7c7b\u578b\u3002\u4f8b\u5982\uff1a\n\n[1, 2, 3.14, 'Hello', null, true];\n\u4e0a\u8ff0\u6570\u7ec4\u5305\u542b6\u4e2a\u5143\u7d20\u3002\u6570\u7ec4\u7528[]\u8868\u793a\uff0c\u5143\u7d20\u4e4b\u95f4\u7528,\u5206\u9694\u3002\n\n\u53e6\u4e00\u79cd\u521b\u5efa\u6570\u7ec4\u7684\u65b9\u6cd5\u662f\u901a\u8fc7Array()\u51fd\u6570\u5b9e\u73b0\uff1a\n\nnew Array(1, 2, 3); \/\/ \u521b\u5efa\u4e86\u6570\u7ec4[1, 2, 3]\n\n\nJavaScript\u7684\u5bf9\u8c61\u662f\u4e00\u7ec4\u7531\u952e-\u503c\u7ec4\u6210\u7684\u65e0\u5e8f\u96c6\u5408\uff0c\u4f8b\u5982\uff1a\n\nvar person = {\n    name: 'Bob',\n    age: 20,\n    tags: ['js', 'web', 'mobile'],\n    city: 'Beijing',\n    hasCar: true,\n    zipcode: null\n};\nJavaScript\u5bf9\u8c61\u7684\u952e\u90fd\u662f\u5b57\u7b26\u4e32\u7c7b\u578b\uff0c\u503c\u53ef\u4ee5\u662f\u4efb\u610f\u6570\u636e\u7c7b\u578b\u3002\n\n\u8981\u83b7\u53d6\u4e00\u4e2a\u5bf9\u8c61\u7684\u5c5e\u6027\uff0c\u6211\u4eec\u7528\u5bf9\u8c61\u53d8\u91cf.\u5c5e\u6027\u540d\u7684\u65b9\u5f0f\uff1a\n\nperson.name; \/\/ 'Bob'\nperson.zipcode; \/\/ null<\/code><\/pre>\n\n\n\n
<\/p>\n\n\n\n
JavaScript\u7684\u5b57\u7b26\u4e32\u5c31\u662f\u7528''<\/code>\u6216\"\"<\/code>\u62ec\u8d77\u6765\u7684\u5b57\u7b26\u8868\u793a\u3002<\/p>\n\n\n\n
\u5982\u679c'<\/code>\u672c\u8eab\u4e5f\u662f\u4e00\u4e2a\u5b57\u7b26\uff0c\u90a3\u5c31\u53ef\u4ee5\u7528\"\"<\/code>\u62ec\u8d77\u6765\uff0c\u6bd4\u5982\"I'm OK\"<\/code><\/p>\n\n\n\n
\u5982\u679c\u5b57\u7b26\u4e32\u5185\u90e8\u65e2\u5305\u542b'<\/code>\u53c8\u5305\u542b\"<\/code>\u600e\u4e48\u529e\uff1f\u53ef\u4ee5\u7528\u8f6c\u4e49\u5b57\u7b26\\<\/code>\u6765\u6807\u8bc6\uff0c\u6bd4\u5982\uff1a<\/p>\n\n\n\n
'I\\'m \\\"OK\\\"!'; \/\/ I'm \"OK\"!\n<\/code><\/pre>\n\n\n\n
\u8868\u793a\u7684\u5b57\u7b26\u4e32\u5185\u5bb9\u662f\uff1aI'm \"OK\"!<\/code><\/p>\n\n\n\n
\u8f6c\u4e49\u5b57\u7b26\\<\/code>\u53ef\u4ee5\u8f6c\u4e49\u5f88\u591a\u5b57\u7b26\uff0c\u6bd4\u5982\\n<\/code>\u8868\u793a\u6362\u884c\uff0c\\t<\/code>\u8868\u793a\u5236\u8868\u7b26\uff0c\u5b57\u7b26\\<\/code>\u672c\u8eab\u4e5f\u8981\u8f6c\u4e49\uff0c\u6240\u4ee5\\\\<\/code>\u8868\u793a\u7684\u5b57\u7b26\u5c31\u662f\\<\/code>\u3002<\/p>\n\n\n\n
ASCII\u5b57\u7b26\u53ef\u4ee5\u4ee5\\x##<\/code>\u5f62\u5f0f\u7684\u5341\u516d\u8fdb\u5236\u8868\u793a\uff0c\u4f8b\u5982\uff1a<\/p>\n\n\n\n
'\\x41'; \/\/ \u5b8c\u5168\u7b49\u540c\u4e8e 'A'\n<\/code><\/pre>\n\n\n\n
\u8fd8\u53ef\u4ee5\u7528\\u####<\/code>\u8868\u793a\u4e00\u4e2aUnicode\u5b57\u7b26\uff1a<\/p>\n\n\n\n
'\\u4e2d\\u6587'; \/\/ \u5b8c\u5168\u7b49\u540c\u4e8e '\u4e2d\u6587'\n\n\u591a\u884c\u5b57\u7b26\u4e32\u7528\\n\u5199\u8d77\u6765\u6bd4\u8f83\u8d39\u4e8b\uff0c\u7528\u53cd\u5f15\u53f7`...`\u8868\u793a\n<\/code><\/pre>\n\n\n\n
\u591a\u4e2a\u5b57\u7b26\u4e32\u8fde\u63a5\u8d77\u6765\uff0c\u53ef\u4ee5\u7528+<\/code>\u53f7\u8fde\u63a5<\/p>\n\n\n\n
\u5982\u679c\u6709\u5f88\u591a\u53d8\u91cf\u9700\u8981\u8fde\u63a5\uff0c\u7528+<\/code>\u53f7\u5c31\u6bd4\u8f83\u9ebb\u70e6\u3002ES6\u65b0\u589e\u4e86\u4e00\u79cd\u6a21\u677f\u5b57\u7b26\u4e32\uff0c\u5b83\u4f1a\u81ea\u52a8\u66ff\u6362\u5b57\u7b26\u4e32\u4e2d\u7684\u53d8\u91cf\uff1a<\/p>\n\n\n\n
let name = '\u5c0f\u660e';\nlet age = 20;\nlet message = `\u4f60\u597d, ${name}, \u4f60\u4eca\u5e74${age}\u5c81\u4e86!`;\nalert(message);\n\n\u83b7\u53d6\u5b57\u7b26\u4e32\u957f\u5ea6\uff1a\n\nlet s = 'Hello, world!';\ns.length; \/\/ 13\n\u8981\u83b7\u53d6\u5b57\u7b26\u4e32\u67d0\u4e2a\u6307\u5b9a\u4f4d\u7f6e\u7684\u5b57\u7b26\uff0c\u4f7f\u7528\u7c7b\u4f3cArray\u7684\u4e0b\u6807\u64cd\u4f5c\uff0c\u7d22\u5f15\u53f7\u4ece0\u5f00\u59cb\uff1a\n\nlet s = 'Hello, world!';\n\ns[0]; \/\/ 'H'\ns[6]; \/\/ ' '\ns[7]; \/\/ 'w'\ns[12]; \/\/ '!'\ns[13]; \/\/ undefined \u8d85\u51fa\u8303\u56f4\u7684\u7d22\u5f15\u4e0d\u4f1a\u62a5\u9519\uff0c\u4f46\u4e00\u5f8b\u8fd4\u56deundefined\n\u9700\u8981\u7279\u522b\u6ce8\u610f\u7684\u662f\uff0c\u5b57\u7b26\u4e32\u662f\u4e0d\u53ef\u53d8\u7684\uff0c\u5982\u679c\u5bf9\u5b57\u7b26\u4e32\u7684\u67d0\u4e2a\u7d22\u5f15\u8d4b\u503c\uff0c\u4e0d\u4f1a\u6709\u4efb\u4f55\u9519\u8bef\uff0c\u4f46\u662f\uff0c\u4e5f\u6ca1\u6709\u4efb\u4f55\u6548\u679c\uff1a\n\nlet s = 'Test';\ns[0] = 'X';\nconsole.log(s); \/\/ s\u4ecd\u7136\u4e3a'Test'\nJavaScript\u4e3a\u5b57\u7b26\u4e32\u63d0\u4f9b\u4e86\u4e00\u4e9b\u5e38\u7528\u65b9\u6cd5\uff0c\u6ce8\u610f\uff0c\u8c03\u7528\u8fd9\u4e9b\u65b9\u6cd5\u672c\u8eab\u4e0d\u4f1a\u6539\u53d8\u539f\u6709\u5b57\u7b26\u4e32\u7684\u5185\u5bb9\uff0c\u800c\u662f\u8fd4\u56de\u4e00\u4e2a\u65b0\u5b57\u7b26\u4e32\uff1a\n\ntoUpperCase\ntoUpperCase()\u628a\u4e00\u4e2a\u5b57\u7b26\u4e32\u5168\u90e8\u53d8\u4e3a\u5927\u5199\uff1a\n\nlet s = 'Hello';\ns.toUpperCase(); \/\/ \u8fd4\u56de'HELLO'\ntoLowerCase\ntoLowerCase()\u628a\u4e00\u4e2a\u5b57\u7b26\u4e32\u5168\u90e8\u53d8\u4e3a\u5c0f\u5199\uff1a\n\nlet s = 'Hello';\nlet lower = s.toLowerCase(); \/\/ \u8fd4\u56de'hello'\u5e76\u8d4b\u503c\u7ed9\u53d8\u91cflower\nlower; \/\/ 'hello'\nindexOf\nindexOf()\u4f1a\u641c\u7d22\u6307\u5b9a\u5b57\u7b26\u4e32\u51fa\u73b0\u7684\u4f4d\u7f6e\uff1a\n\nlet s = 'hello, world';\ns.indexOf('world'); \/\/ \u8fd4\u56de7\ns.indexOf('World'); \/\/ \u6ca1\u6709\u627e\u5230\u6307\u5b9a\u7684\u5b50\u4e32\uff0c\u8fd4\u56de-1\nsubstring\nsubstring()\u8fd4\u56de\u6307\u5b9a\u7d22\u5f15\u533a\u95f4\u7684\u5b50\u4e32\uff1a\n\nlet s = 'hello, world'\ns.substring(0, 5); \/\/ \u4ece\u7d22\u5f150\u5f00\u59cb\u52305\uff08\u4e0d\u5305\u62ec5\uff09\uff0c\u8fd4\u56de'hello'\ns.substring(7); \/\/ \u4ece\u7d22\u5f157\u5f00\u59cb\u5230\u7ed3\u675f\uff0c\u8fd4\u56de'world'<\/code><\/pre>\n\n\n\n
Array<\/code>\u53ef\u4ee5\u5305\u542b\u4efb\u610f\u6570\u636e\u7c7b\u578b\uff0c\u5e76\u901a\u8fc7\u7d22\u5f15\u6765\u8bbf\u95ee\u6bcf\u4e2a\u5143\u7d20<\/p>\n\n\n\n
<\/p>\n\n\n\n
indexOf<\/h3>\n\n\n\n
\u4e0eString\u7c7b\u4f3c\uff0cArray<\/code>\u4e5f\u53ef\u4ee5\u901a\u8fc7indexOf()<\/code>\u6765\u641c\u7d22\u4e00\u4e2a\u6307\u5b9a\u7684\u5143\u7d20\u7684\u4f4d\u7f6e\uff1a<\/p>\n\n\n\n
let arr = [10, 20, '30', 'xyz'];\narr.indexOf(10); \/\/ \u5143\u7d2010\u7684\u7d22\u5f15\u4e3a0\narr.indexOf(20); \/\/ \u5143\u7d2020\u7684\u7d22\u5f15\u4e3a1\narr.indexOf(30); \/\/ \u5143\u7d2030\u6ca1\u6709\u627e\u5230\uff0c\u8fd4\u56de-1\narr.indexOf('30'); \/\/ \u5143\u7d20'30'\u7684\u7d22\u5f15\u4e3a2\n<\/code><\/pre>\n\n\n\n
\u6ce8\u610f\u4e86\uff0c\u6570\u5b5730<\/code>\u548c\u5b57\u7b26\u4e32'30'<\/code>\u662f\u4e0d\u540c\u7684\u5143\u7d20\u3002<\/p>\n\n\n\n
slice<\/h3>\n\n\n\n
slice()<\/code>\u5c31\u662f\u5bf9\u5e94String\u7684substring()<\/code>\u7248\u672c\uff0c\u5b83\u622a\u53d6Array<\/code>\u7684\u90e8\u5206\u5143\u7d20\uff0c\u7136\u540e\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684Array<\/code>\uff1a<\/p>\n\n\n\n
let arr = ['A', 'B', 'C', 'D', 'E', 'F', 'G'];\narr.slice(0, 3); \/\/ \u4ece\u7d22\u5f150\u5f00\u59cb\uff0c\u5230\u7d22\u5f153\u7ed3\u675f\uff0c\u4f46\u4e0d\u5305\u62ec\u7d22\u5f153: ['A', 'B', 'C']\narr.slice(3); \/\/ \u4ece\u7d22\u5f153\u5f00\u59cb\u5230\u7ed3\u675f: ['D', 'E', 'F', 'G']\n<\/code><\/pre>\n\n\n\n
\u6ce8\u610f\u5230slice()<\/code>\u7684\u8d77\u6b62\u53c2\u6570\u5305\u62ec\u5f00\u59cb\u7d22\u5f15\uff0c\u4e0d\u5305\u62ec\u7ed3\u675f\u7d22\u5f15\u3002<\/p>\n\n\n\n
\u5982\u679c\u4e0d\u7ed9slice()<\/code>\u4f20\u9012\u4efb\u4f55\u53c2\u6570\uff0c\u5b83\u5c31\u4f1a\u4ece\u5934\u5230\u5c3e\u622a\u53d6\u6240\u6709\u5143\u7d20\u3002\u5229\u7528\u8fd9\u4e00\u70b9\uff0c\u6211\u4eec\u53ef\u4ee5\u5f88\u5bb9\u6613\u5730\u590d\u5236\u4e00\u4e2aArray<\/code>\uff1a<\/p>\n\n\n\n
let arr = ['A', 'B', 'C', 'D', 'E', 'F', 'G'];\nlet aCopy = arr.slice();\naCopy; \/\/ ['A', 'B', 'C', 'D', 'E', 'F', 'G']\naCopy === arr; \/\/ false\n<\/code><\/pre>\n\n\n\n
push\u548cpop<\/h3>\n\n\n\n
push()<\/code>\u5411Array<\/code>\u7684\u672b\u5c3e\u6dfb\u52a0\u82e5\u5e72\u5143\u7d20\uff0cpop()<\/code>\u5219\u628aArray<\/code>\u7684\u6700\u540e\u4e00\u4e2a\u5143\u7d20\u5220\u9664\u6389\uff1a<\/p>\n\n\n\n
let arr = [1, 2];\narr.push('A', 'B'); \/\/ \u8fd4\u56deArray\u65b0\u7684\u957f\u5ea6: 4\narr; \/\/ [1, 2, 'A', 'B']\narr.pop(); \/\/ pop()\u8fd4\u56de'B'\narr; \/\/ [1, 2, 'A']\narr.pop(); arr.pop(); arr.pop(); \/\/ \u8fde\u7eedpop 3\u6b21\narr; \/\/ []\narr.pop(); \/\/ \u7a7a\u6570\u7ec4\u7ee7\u7eedpop\u4e0d\u4f1a\u62a5\u9519\uff0c\u800c\u662f\u8fd4\u56deundefined\narr; \/\/ []\n<\/code><\/pre>\n\n\n\n
unshift\u548cshift<\/h3>\n\n\n\n
\u5982\u679c\u8981\u5f80Array<\/code>\u7684\u5934\u90e8\u6dfb\u52a0\u82e5\u5e72\u5143\u7d20\uff0c\u4f7f\u7528unshift()<\/code>\u65b9\u6cd5\uff0cshift()<\/code>\u65b9\u6cd5\u5219\u628aArray<\/code>\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\u5220\u6389\uff1a<\/p>\n\n\n\n
let arr = [1, 2];\narr.unshift('A', 'B'); \/\/ \u8fd4\u56deArray\u65b0\u7684\u957f\u5ea6: 4\narr; \/\/ ['A', 'B', 1, 2]\narr.shift(); \/\/ 'A'\narr; \/\/ ['B', 1, 2]\narr.shift(); arr.shift(); arr.shift(); \/\/ \u8fde\u7eedshift 3\u6b21\narr; \/\/ []\narr.shift(); \/\/ \u7a7a\u6570\u7ec4\u7ee7\u7eedshift\u4e0d\u4f1a\u62a5\u9519\uff0c\u800c\u662f\u8fd4\u56deundefined\narr; \/\/ []\n<\/code><\/pre>\n\n\n\n
sort<\/h3>\n\n\n\n
sort()<\/code>\u53ef\u4ee5\u5bf9\u5f53\u524dArray<\/code>\u8fdb\u884c\u6392\u5e8f\uff0c\u5b83\u4f1a\u76f4\u63a5\u4fee\u6539\u5f53\u524dArray<\/code>\u7684\u5143\u7d20\u4f4d\u7f6e\uff0c\u76f4\u63a5\u8c03\u7528\u65f6\uff0c\u6309\u7167\u9ed8\u8ba4\u987a\u5e8f\u6392\u5e8f\uff1a<\/p>\n\n\n\n
let arr = ['B', 'C', 'A'];\narr.sort();\narr; \/\/ ['A', 'B', 'C']\n<\/code><\/pre>\n\n\n\n
\u80fd\u5426\u6309\u7167\u6211\u4eec\u81ea\u5df1\u6307\u5b9a\u7684\u987a\u5e8f\u6392\u5e8f\u5462\uff1f\u5b8c\u5168\u53ef\u4ee5\uff0c\u6211\u4eec\u5c06\u5728\u540e\u9762\u7684\u51fd\u6570\u4e2d\u8bb2\u5230\u3002<\/p>\n\n\n\n
reverse<\/h3>\n\n\n\n
reverse()<\/code>\u628a\u6574\u4e2aArray<\/code>\u7684\u5143\u7d20\u7ed9\u8c03\u4e2a\u4e2a\uff0c\u4e5f\u5c31\u662f\u53cd\u8f6c\uff1a<\/p>\n\n\n\n
let arr = ['one', 'two', 'three'];\narr.reverse(); \narr; \/\/ ['three', 'two', 'one']\n<\/code><\/pre>\n\n\n\n
splice<\/h3>\n\n\n\n
splice()<\/code>\u65b9\u6cd5\u662f\u4fee\u6539Array<\/code>\u7684\u201c\u4e07\u80fd\u65b9\u6cd5\u201d\uff0c\u5b83\u53ef\u4ee5\u4ece\u6307\u5b9a\u7684\u7d22\u5f15\u5f00\u59cb\u5220\u9664\u82e5\u5e72\u5143\u7d20\uff0c\u7136\u540e\u518d\u4ece\u8be5\u4f4d\u7f6e\u6dfb\u52a0\u82e5\u5e72\u5143\u7d20\uff1a<\/p>\n\n\n\n
let arr = ['Microsoft', 'Apple', 'Yahoo', 'AOL', 'Excite', 'Oracle'];\n\/\/ \u4ece\u7d22\u5f152\u5f00\u59cb\u5220\u96643\u4e2a\u5143\u7d20,\u7136\u540e\u518d\u6dfb\u52a0\u4e24\u4e2a\u5143\u7d20:\narr.splice(2, 3, 'Google', 'Facebook'); \/\/ \u8fd4\u56de\u5220\u9664\u7684\u5143\u7d20 ['Yahoo', 'AOL', 'Excite']\narr; \/\/ ['Microsoft', 'Apple', 'Google', 'Facebook', 'Oracle']\n\/\/ \u53ea\u5220\u9664,\u4e0d\u6dfb\u52a0:\narr.splice(2, 2); \/\/ ['Google', 'Facebook']\narr; \/\/ ['Microsoft', 'Apple', 'Oracle']\n\/\/ \u53ea\u6dfb\u52a0,\u4e0d\u5220\u9664:\narr.splice(2, 0, 'Google', 'Facebook'); \/\/ \u8fd4\u56de[],\u56e0\u4e3a\u6ca1\u6709\u5220\u9664\u4efb\u4f55\u5143\u7d20\narr; \/\/ ['Microsoft', 'Apple', 'Google', 'Facebook', 'Oracle']\n<\/code><\/pre>\n\n\n\n
concat<\/h3>\n\n\n\n
concat()<\/code>\u65b9\u6cd5\u628a\u5f53\u524d\u7684Array<\/code>\u548c\u53e6\u4e00\u4e2aArray<\/code>\u8fde\u63a5\u8d77\u6765\uff0c\u5e76\u8fd4\u56de\u4e00\u4e2a\u65b0\u7684Array<\/code>\uff1a<\/p>\n\n\n\n
let arr = ['A', 'B', 'C'];\nlet added = arr.concat([1, 2, 3]);\nadded; \/\/ ['A', 'B', 'C', 1, 2, 3]\narr; \/\/ ['A', 'B', 'C']\n<\/code><\/pre>\n\n\n\n
\u8bf7\u6ce8\u610f<\/em>\uff0cconcat()<\/code>\u65b9\u6cd5\u5e76\u6ca1\u6709\u4fee\u6539\u5f53\u524dArray<\/code>\uff0c\u800c\u662f\u8fd4\u56de\u4e86\u4e00\u4e2a\u65b0\u7684Array<\/code>\u3002<\/p>\n\n\n\n
\u5b9e\u9645\u4e0a\uff0cconcat()<\/code>\u65b9\u6cd5\u53ef\u4ee5\u63a5\u6536\u4efb\u610f\u4e2a\u5143\u7d20\u548cArray<\/code>\uff0c\u5e76\u4e14\u81ea\u52a8\u628aArray<\/code>\u62c6\u5f00\uff0c\u7136\u540e\u5168\u90e8\u6dfb\u52a0\u5230\u65b0\u7684Array<\/code>\u91cc\uff1a<\/p>\n\n\n\n
let arr = ['A', 'B', 'C'];\narr.concat(1, 2, [3, 4]); \/\/ ['A', 'B', 'C', 1, 2, 3, 4]\n<\/code><\/pre>\n\n\n\n
join<\/h3>\n\n\n\n
join()<\/code>\u65b9\u6cd5\u662f\u4e00\u4e2a\u975e\u5e38\u5b9e\u7528\u7684\u65b9\u6cd5\uff0c\u5b83\u628a\u5f53\u524dArray<\/code>\u7684\u6bcf\u4e2a\u5143\u7d20\u90fd\u7528\u6307\u5b9a\u7684\u5b57\u7b26\u4e32\u8fde\u63a5\u8d77\u6765\uff0c\u7136\u540e\u8fd4\u56de\u8fde\u63a5\u540e\u7684\u5b57\u7b26\u4e32\uff1a<\/p>\n\n\n\n
let arr = ['A', 'B', 'C', 1, 2, 3];\narr.join('-'); \/\/ 'A-B-C-1-2-3'<\/code><\/pre>\n\n\n\n
<\/p>\n\n\n\n
JavaScript\u7684\u5bf9\u8c61\u6709\u4e2a\u5c0f\u95ee\u9898\uff0c\u5c31\u662f\u952e\u5fc5\u987b\u662f\u5b57\u7b26\u4e32\u3002\u4f46\u5b9e\u9645\u4e0aNumber\u6216\u8005\u5176\u4ed6\u6570\u636e\u7c7b\u578b\u4f5c\u4e3a\u952e\u4e5f\u662f\u975e\u5e38\u5408\u7406\u7684\u3002<\/p>\n\n\n\n
\u4e3a\u4e86\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\uff0c\u6700\u65b0\u7684ES6\u89c4\u8303\u5f15\u5165\u4e86\u65b0\u7684\u6570\u636e\u7c7b\u578bMap<\/code><\/p>\n\n\n\n
Map<\/code>\u662f\u4e00\u7ec4\u952e\u503c\u5bf9\u7684\u7ed3\u6784\uff0c\u5177\u6709\u6781\u5feb\u7684\u67e5\u627e\u901f\u5ea6\u3002<\/p>\n\n\n\n
\u4e3e\u4e2a\u4f8b\u5b50\uff0c\u5047\u8bbe\u8981\u6839\u636e\u540c\u5b66\u7684\u540d\u5b57\u67e5\u627e\u5bf9\u5e94\u7684\u6210\u7ee9\uff0c\u5982\u679c\u7528Array<\/code>\u5b9e\u73b0\uff0c\u9700\u8981\u4e24\u4e2aArray<\/code>\uff1a<\/p>\n\n\n\n
let names = ['Michael', 'Bob', 'Tracy'];\nlet scores = [95, 75, 85];\n<\/code><\/pre>\n\n\n\n
\u7ed9\u5b9a\u4e00\u4e2a\u540d\u5b57\uff0c\u8981\u67e5\u627e\u5bf9\u5e94\u7684\u6210\u7ee9\uff0c\u5c31\u5148\u8981\u5728names\u4e2d\u627e\u5230\u5bf9\u5e94\u7684\u4f4d\u7f6e\uff0c\u518d\u4ecescores\u53d6\u51fa\u5bf9\u5e94\u7684\u6210\u7ee9\uff0cArray\u8d8a\u957f\uff0c\u8017\u65f6\u8d8a\u957f\u3002<\/p>\n\n\n\n
\u5982\u679c\u7528Map\u5b9e\u73b0\uff0c\u53ea\u9700\u8981\u4e00\u4e2a\u201c\u540d\u5b57\u201d-\u201c\u6210\u7ee9\u201d\u7684\u5bf9\u7167\u8868\uff0c\u76f4\u63a5\u6839\u636e\u540d\u5b57\u67e5\u627e\u6210\u7ee9\uff0c\u65e0\u8bba\u8fd9\u4e2a\u8868\u6709\u591a\u5927\uff0c\u67e5\u627e\u901f\u5ea6\u90fd\u4e0d\u4f1a\u53d8\u6162\u3002\u7528JavaScript\u5199\u4e00\u4e2aMap\u5982\u4e0b\uff1a<\/p>\n\n\n\n
let m = new Map([['Michael', 95], ['Bob', 75], ['Tracy', 85]]);\nm.get('Michael'); \/\/ 95\n<\/code><\/pre>\n\n\n\n
\u521d\u59cb\u5316Map<\/code>\u9700\u8981\u4e00\u4e2a\u4e8c\u7ef4\u6570\u7ec4\uff0c\u6216\u8005\u76f4\u63a5\u521d\u59cb\u5316\u4e00\u4e2a\u7a7aMap<\/code>\u3002Map<\/code>\u5177\u6709\u4ee5\u4e0b\u65b9\u6cd5\uff1a<\/p>\n\n\n\n
let m = new Map(); \/\/ \u7a7aMap\nm.set('Adam', 67); \/\/ \u6dfb\u52a0\u65b0\u7684key-value\nm.set('Bob', 59);\nm.has('Adam'); \/\/ \u662f\u5426\u5b58\u5728key 'Adam': true\nm.get('Adam'); \/\/ 67\nm.delete('Adam'); \/\/ \u5220\u9664key 'Adam'\nm.get('Adam'); \/\/ undefined\n<\/code><\/pre>\n\n\n\n
Set<\/code>\u548cMap<\/code>\u7c7b\u4f3c\uff0c\u4e5f\u662f\u4e00\u7ec4key\u7684\u96c6\u5408\uff0c\u4f46\u4e0d\u5b58\u50a8value\u3002\u7531\u4e8ekey\u4e0d\u80fd\u91cd\u590d\uff0c\u6240\u4ee5\uff0c\u5728Set<\/code>\u4e2d\uff0c\u6ca1\u6709\u91cd\u590d\u7684key\u3002<\/p>\n\n\n\n
\u8981\u521b\u5efa\u4e00\u4e2aSet<\/code>\uff0c\u9700\u8981\u63d0\u4f9b\u4e00\u4e2aArray<\/code>\u4f5c\u4e3a\u8f93\u5165\uff0c\u6216\u8005\u76f4\u63a5\u521b\u5efa\u4e00\u4e2a\u7a7aSet<\/code>\uff1a<\/p>\n\n\n\n
let s1 = new Set(); \/\/ \u7a7aSet\nlet s2 = new Set([1, 2, 3]); \/\/ \u542b1, 2, 3\n<\/code><\/pre>\n\n\n\n
\u91cd\u590d\u5143\u7d20\u5728Set<\/code>\u4e2d\u81ea\u52a8\u88ab\u8fc7\u6ee4\uff1a<\/p>\n\n\n\n
let s = new Set([1, 2, 3, 3, '3']);\ns; \/\/ Set {1, 2, 3, \"3\"}\n<\/code><\/pre>\n\n\n\n
\u6ce8\u610f\u6570\u5b573<\/code>\u548c\u5b57\u7b26\u4e32'3'<\/code>\u662f\u4e0d\u540c\u7684\u5143\u7d20\u3002<\/p>\n\n\n\n
\u901a\u8fc7add(key)<\/code>\u65b9\u6cd5\u53ef\u4ee5\u6dfb\u52a0\u5143\u7d20\u5230Set<\/code>\u4e2d\uff0c\u53ef\u4ee5\u91cd\u590d\u6dfb\u52a0\uff0c\u4f46\u4e0d\u4f1a\u6709\u6548\u679c\uff1a<\/p>\n\n\n\n
s.add(4);\ns; \/\/ Set {1, 2, 3, 4}\ns.add(4);\ns; \/\/ \u4ecd\u7136\u662f Set {1, 2, 3, 4}\n<\/code><\/pre>\n\n\n\n
\u901a\u8fc7delete(key)<\/code>\u65b9\u6cd5\u53ef\u4ee5\u5220\u9664\u5143\u7d20<\/p>\n\n\n\n
\u904d\u5386Array<\/code>\u53ef\u4ee5\u91c7\u7528\u4e0b\u6807\u5faa\u73af\uff0c\u904d\u5386Map<\/code>\u548cSet<\/code>\u5c31\u65e0\u6cd5\u4f7f\u7528\u4e0b\u6807\u3002\u4e3a\u4e86\u7edf\u4e00\u96c6\u5408\u7c7b\u578b\uff0cES6\u6807\u51c6\u5f15\u5165\u4e86\u65b0\u7684iterable<\/code>\u7c7b\u578b\uff0cArray<\/code>\u3001Map<\/code>\u548cSet<\/code>\u90fd\u5c5e\u4e8eiterable<\/code>\u7c7b\u578b\u3002<\/p>\n\n\n\n
\u5177\u6709iterable<\/code>\u7c7b\u578b\u7684\u96c6\u5408\u53ef\u4ee5\u901a\u8fc7\u65b0\u7684for ... of<\/code>\u5faa\u73af\u6765\u904d\u5386<\/p>\n\n\n\n
let a = ['A', 'B', 'C'];\nlet s = new Set(['A', 'B', 'C']);\nlet m = new Map([[1, 'x'], [2, 'y'], [3, 'z']]);\nfor (let x of a) { \/\/ \u904d\u5386Array\n    console.log(x);\n}\nfor (let x of s) { \/\/ \u904d\u5386Set\n    console.log(x);\n}\nfor (let x of m) { \/\/ \u904d\u5386Map\n    console.log(x[0] + '=' + x[1]);\n}<\/code><\/pre>\n\n\n\n
<\/p>\n\n\n\n
\u6211\u4eec\u5efa\u8bae\u7528for … of\uff0c\u800c\u4e0d\u662ffor … in  \u66f4\u597d\u7684\u65b9\u5f0f\u662f\u76f4\u63a5\u4f7f\u7528iterable<\/code>\u5185\u7f6e\u7684forEach<\/code>\u65b9\u6cd5\uff0c\u5b83\u63a5\u6536\u4e00\u4e2a\u51fd\u6570\uff0c\u6bcf\u6b21\u8fed\u4ee3\u5c31\u81ea\u52a8\u56de\u8c03\u8be5\u51fd\u6570\u3002\u4ee5Array<\/code>\u4e3a\u4f8b\uff1a<\/p>\n\n\n\n
let a = [‘A’, ‘B’, ‘C’];
a.forEach(function (element, index, array) {
\/\/ element: \u6307\u5411\u5f53\u524d\u5143\u7d20\u7684\u503c
\/\/ index: \u6307\u5411\u5f53\u524d\u7d22\u5f15
\/\/ array: \u6307\u5411Array\u5bf9\u8c61\u672c\u8eab
console.log(${element}, index = ${index}<\/code>);
});<\/p>\n\n\n\n
\u5173\u952e\u5b57arguments<\/code>\uff0c\u5b83\u53ea\u5728\u51fd\u6570\u5185\u90e8\u8d77\u4f5c\u7528\uff0c\u5e76\u4e14\u6c38\u8fdc\u6307\u5411\u5f53\u524d\u51fd\u6570\u7684\u8c03\u7528\u8005\u4f20\u5165\u7684\u6240\u6709\u53c2\u6570<\/p>\n\n\n\n
\u5b9e\u9645\u4e0aarguments<\/code>\u6700\u5e38\u7528\u4e8e\u5224\u65ad\u4f20\u5165\u53c2\u6570\u7684\u4e2a\u6570\u3002\u4f60\u53ef\u80fd\u4f1a\u770b\u5230\u8fd9\u6837\u7684\u5199\u6cd5\uff1a<\/p>\n\n\n\n
\/\/ foo(a[, b], c)\n\/\/ \u63a5\u65362~3\u4e2a\u53c2\u6570\uff0cb\u662f\u53ef\u9009\u53c2\u6570\uff0c\u5982\u679c\u53ea\u4f202\u4e2a\u53c2\u6570\uff0cb\u9ed8\u8ba4\u4e3anull\uff1a\nfunction foo(a, b, c) {\n    if (arguments.length === 2) {\n        \/\/ \u5b9e\u9645\u62ff\u5230\u7684\u53c2\u6570\u662fa\u548cb\uff0cc\u4e3aundefined\n        c = b; \/\/ \u628ab\u8d4b\u7ed9c\n        b = null; \/\/ b\u53d8\u4e3a\u9ed8\u8ba4\u503c\n    }\n    \/\/ ...\n}<\/code><\/pre>\n\n\n\n
\u7531\u4e8eJavaScript\u51fd\u6570\u5141\u8bb8\u63a5\u6536\u4efb\u610f\u4e2a\u53c2\u6570\uff0c\u4e8e\u662f\u6211\u4eec\u5c31\u4e0d\u5f97\u4e0d\u7528arguments<\/code>\u6765\u83b7\u53d6\u6240\u6709\u53c2\u6570\uff1a<\/p>\n\n\n\n
function foo(a, b) {\n    let i, rest = [];\n    if (arguments.length > 2) {\n        for (i = 2; i<arguments.length; i++) {\n            rest.push(arguments[i]);\n        }\n    }\n    console.log('a = ' + a);\n    console.log('b = ' + b);\n    console.log(rest);\n}\n<\/code><\/pre>\n\n\n\n
\u4e3a\u4e86\u83b7\u53d6\u9664\u4e86\u5df2\u5b9a\u4e49\u53c2\u6570a<\/code>\u3001b<\/code>\u4e4b\u5916\u7684\u53c2\u6570\uff0c\u6211\u4eec\u4e0d\u5f97\u4e0d\u7528arguments<\/code>\uff0c\u5e76\u4e14\u5faa\u73af\u8981\u4ece\u7d22\u5f152<\/code>\u5f00\u59cb\u4ee5\u4fbf\u6392\u9664\u524d\u4e24\u4e2a\u53c2\u6570\uff0c\u8fd9\u79cd\u5199\u6cd5\u5f88\u522b\u626d\uff0c\u53ea\u662f\u4e3a\u4e86\u83b7\u5f97\u989d\u5916\u7684rest<\/code>\u53c2\u6570\uff0c\u6709\u6ca1\u6709\u66f4\u597d\u7684\u65b9\u6cd5\uff1f<\/p>\n\n\n\n
ES6\u6807\u51c6\u5f15\u5165\u4e86rest\u53c2\u6570\uff0c\u4e0a\u9762\u7684\u51fd\u6570\u53ef\u4ee5\u6539\u5199\u4e3a\uff1a<\/p>\n\n\n\n
function foo(a, b, ...rest) {\n    console.log('a = ' + a);\n    console.log('b = ' + b);\n    console.log(rest);\n}\n\nfoo(1, 2, 3, 4, 5);\n\/\/ \u7ed3\u679c:\n\/\/ a = 1\n\/\/ b = 2\n\/\/ Array [ 3, 4, 5 ]\n\nfoo(1);\n\/\/ \u7ed3\u679c:\n\/\/ a = 1\n\/\/ b = undefined\n\/\/ Array []\n<\/code><\/pre>\n\n\n\n
rest\u53c2\u6570\u53ea\u80fd\u5199\u5728\u6700\u540e\uff0c\u524d\u9762\u7528...<\/code>\u6807\u8bc6\uff0c\u4ece\u8fd0\u884c\u7ed3\u679c\u53ef\u77e5\uff0c\u4f20\u5165\u7684\u53c2\u6570\u5148\u7ed1\u5b9aa<\/code>\u3001b<\/code>\uff0c\u591a\u4f59\u7684\u53c2\u6570\u4ee5\u6570\u7ec4\u5f62\u5f0f\u4ea4\u7ed9\u53d8\u91cfrest<\/code>\uff0c\u6240\u4ee5\uff0c\u4e0d\u518d\u9700\u8981arguments<\/code>\u6211\u4eec\u5c31\u83b7\u53d6\u4e86\u5168\u90e8\u53c2\u6570\u3002<\/p>\n\n\n\n
\u5982\u679c\u4f20\u5165\u7684\u53c2\u6570\u8fde\u6b63\u5e38\u5b9a\u4e49\u7684\u53c2\u6570\u90fd\u6ca1\u586b\u6ee1\uff0c\u4e5f\u4e0d\u8981\u7d27\uff0crest\u53c2\u6570\u4f1a\u63a5\u6536\u4e00\u4e2a\u7a7a\u6570\u7ec4\uff08\u6ce8\u610f\u4e0d\u662fundefined<\/code>\uff09<\/p>\n\n\n\n
JavaScript\u9ed8\u8ba4\u6709\u4e00\u4e2a\u5168\u5c40\u5bf9\u8c61window<\/code>\uff0c\u5168\u5c40\u4f5c\u7528\u57df\u7684\u53d8\u91cf\u5b9e\u9645\u4e0a\u88ab\u7ed1\u5b9a\u5230window<\/code>\u7684\u4e00\u4e2a\u5c5e\u6027,\u4ee5\u53d8\u91cf\u65b9\u5f0fvar foo = function () {}<\/code>\u5b9a\u4e49\u7684\u51fd\u6570\u5b9e\u9645\u4e0a\u4e5f\u662f\u4e00\u4e2a\u5168\u5c40\u53d8\u91cf\uff0c\u56e0\u6b64\uff0c\u9876\u5c42\u51fd\u6570\u7684\u5b9a\u4e49\u4e5f\u88ab\u89c6\u4e3a\u4e00\u4e2a\u5168\u5c40\u53d8\u91cf\uff0c\u5e76\u7ed1\u5b9a\u5230window<\/code>\u5bf9\u8c61\uff1a<\/p>\n\n\n\n
function foo() {\n    alert('foo');\n}\n\nfoo(); \/\/ \u76f4\u63a5\u8c03\u7528foo()\nwindow.foo(); \/\/ \u901a\u8fc7window.foo()\u8c03\u7528\n<\/code><\/pre>\n\n\n\n
\u8fdb\u4e00\u6b65\u5927\u80c6\u5730\u731c\u6d4b\uff0c\u6211\u4eec\u6bcf\u6b21\u76f4\u63a5\u8c03\u7528\u7684alert()<\/code>\u51fd\u6570\u5176\u5b9e\u4e5f\u662fwindow<\/code>\u7684\u4e00\u4e2a\u53d8\u91cf<\/p>\n\n\n\n
<\/p>\n\n\n\n
<\/p>\n\n\n\n
<\/p>\n\n\n\n
\u9ad8\u9636\u51fd\u6570<\/p>\n\n\n\n
map<\/h3>\n\n\n\n
\u4e3e\u4f8b\u8bf4\u660e\uff0c\u6bd4\u5982\u6211\u4eec\u6709\u4e00\u4e2a\u51fd\u6570f(x)=x2<\/sup>\uff0c\u8981\u628a\u8fd9\u4e2a\u51fd\u6570\u4f5c\u7528\u5728\u4e00\u4e2a\u6570\u7ec4[1, 2, 3, 4, 5, 6, 7, 8, 9]<\/code>\u4e0a\uff0c\u5c31\u53ef\u4ee5\u7528map<\/code>\u5b9e\u73b0\u5982\u4e0b\uff1a<\/p>\n\n\n\n
            f(x) = x * x\n\n                  \u2502\n                  \u2502\n  \u250c\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2510\n  \u2502   \u2502   \u2502   \u2502   \u2502   \u2502   \u2502   \u2502   \u2502\n  \u25bc   \u25bc   \u25bc   \u25bc   \u25bc   \u25bc   \u25bc   \u25bc   \u25bc\n\n[ 1   2   3   4   5   6   7   8   9 ]\n\n  \u2502   \u2502   \u2502   \u2502   \u2502   \u2502   \u2502   \u2502   \u2502\n  \u2502   \u2502   \u2502   \u2502   \u2502   \u2502   \u2502   \u2502   \u2502\n  \u25bc   \u25bc   \u25bc   \u25bc   \u25bc   \u25bc   \u25bc   \u25bc   \u25bc\n\n[ 1   4   9  16  25  36  49  64  81 ]\n<\/code><\/pre>\n\n\n\n
\u7531\u4e8emap()<\/code>\u65b9\u6cd5\u5b9a\u4e49\u5728JavaScript\u7684Array<\/code>\u4e2d\uff0c\u6211\u4eec\u8c03\u7528Array<\/code>\u7684map()<\/code>\u65b9\u6cd5\uff0c\u4f20\u5165\u6211\u4eec\u81ea\u5df1\u7684\u51fd\u6570\uff0c\u5c31\u5f97\u5230\u4e86\u4e00\u4e2a\u65b0\u7684Array<\/code>\u4f5c\u4e3a\u7ed3\u679c\uff1a<\/p>\n\n\n\n
function pow(x) {
return x * x;
}<\/p>\n\n\n\n
let arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];
let results = arr.map(pow); \/\/\u7ed3\u679c [1, 4, 9, 16, 25, 36, 49, 64, 81]<\/p>\n\n\n\n
\u8981\u533a\u522b\u4e8e\u4e0a\u9875\u7684Map,\u4e0a\u9762\u7684Map\u662f\u4e00\u4e2a\u6570\u636e\u7ed3\u6784\uff0c\u4e00\u4e9b\u952e\u503c\u5bf9\uff0c\u8fd9\u91cc\u662f\u4e00\u4e2a\u9ad8\u9636\u51fd\u6570<\/p>\n\n\n\n
reduce<\/h3>\n\n\n\n
\u518d\u770breduce\u7684\u7528\u6cd5\u3002Array\u7684reduce()<\/code>\u628a\u4e00\u4e2a\u51fd\u6570\u4f5c\u7528\u5728\u8fd9\u4e2aArray<\/code>\u7684[x1, x2, x3...]<\/code>\u4e0a\uff0c\u8fd9\u4e2a\u51fd\u6570\u5fc5\u987b\u63a5\u6536\u4e24\u4e2a\u53c2\u6570\uff0creduce()<\/code>\u628a\u7ed3\u679c\u7ee7\u7eed\u548c\u5e8f\u5217\u7684\u4e0b\u4e00\u4e2a\u5143\u7d20\u505a\u7d2f\u79ef\u8ba1\u7b97\uff0c\u5176\u6548\u679c\u5c31\u662f\uff1a<\/p>\n\n\n\n
[x1, x2, x3, x4].reduce(f) = f(f(f(x1, x2), x3), x4)\n<\/code><\/pre>\n\n\n\n
\u6bd4\u65b9\u8bf4\u5bf9\u4e00\u4e2aArray<\/code>\u6c42\u548c\uff0c\u5c31\u53ef\u4ee5\u7528reduce<\/code>\u5b9e\u73b0\uff1a<\/p>\n\n\n\n
let arr = [1, 3, 5, 7, 9];\narr.reduce(function (x, y) {\n    return x + y;\n}); \/\/ 25<\/code><\/pre>\n\n\n\n
filter\u4e5f\u662f\u4e00\u4e2a\u5e38\u7528\u7684\u64cd\u4f5c\uff0c\u5b83\u7528\u4e8e\u628aArray<\/code>\u7684\u67d0\u4e9b\u5143\u7d20\u8fc7\u6ee4\u6389\uff0c\u7136\u540e\u8fd4\u56de\u5269\u4e0b\u7684\u5143\u7d20\u3002<\/p>\n\n\n\n
filter()<\/code>\u628a\u4f20\u5165\u7684\u51fd\u6570\u4f9d\u6b21\u4f5c\u7528\u4e8e\u6bcf\u4e2a\u5143\u7d20\uff0c\u7136\u540e\u6839\u636e\u8fd4\u56de\u503c\u662ftrue<\/code>\u8fd8\u662ffalse<\/code>\u51b3\u5b9a\u4fdd\u7559\u8fd8\u662f\u4e22\u5f03\u8be5\u5143\u7d20\u3002<\/p>\n\n\n\n
\u4f8b\u5982\uff0c\u5728\u4e00\u4e2aArray<\/code>\u4e2d\uff0c\u5220\u6389\u5076\u6570\uff0c\u53ea\u4fdd\u7559\u5947\u6570\uff0c\u53ef\u4ee5\u8fd9\u4e48\u5199\uff1a<\/p>\n\n\n\n
let arr = [1, 2, 4, 5, 6, 9, 10, 15];\nlet r = arr.filter(function (x) {\n    return x % 2 !== 0;\n});\nr; \/\/ [1, 5, 9, 15]<\/code><\/pre>\n\n\n\n
sort()<\/code>\u65b9\u6cd5\u662f\u7528\u4e8e\u6392\u5e8f\u7684\uff0c \u8981\u6ce8\u610f\u7684\u662f\u9ed8\u8ba4\u628a\u6240\u6709\u5143\u7d20\u5148\u8f6c\u6362\u4e3aString\u518d\u6392\u5e8f\uff0c\u6240\u4ee5'10'<\/code>\u6392\u5728\u4e86'2'<\/code>\u7684\u524d\u9762\uff0c\u56e0\u4e3a\u5b57\u7b26'1'<\/code>\u6bd4\u5b57\u7b26'2'<\/code>\u7684ASCII\u7801\u5c0f\uff0c\u5e78\u8fd0\u7684\u662f\uff0csort()<\/code>\u65b9\u6cd5\u4e5f\u662f\u4e00\u4e2a\u9ad8\u9636\u51fd\u6570\uff0c\u5b83\u8fd8\u53ef\u4ee5\u63a5\u6536\u4e00\u4e2a\u6bd4\u8f83\u51fd\u6570\u6765\u5b9e\u73b0\u81ea\u5b9a\u4e49\u7684\u6392\u5e8f\u3002<\/p>\n\n\n\n
\u8981\u6309\u6570\u5b57\u5927\u5c0f\u6392\u5e8f\uff0c\u6211\u4eec\u53ef\u4ee5\u8fd9\u4e48\u5199\uff1a<\/p>\n\n\n\n
let arr = [10, 20, 1, 2];<\/p>\n\n\n\n
arr.sort(function (x, y) {
if (x < y) { return -1; } if (x > y) {
return 1;
}
return 0;
});<\/p>\n\n\n\n
console.log(arr); \/\/ [1, 2, 10, 20]<\/p>\n\n\n\n
every()<\/code>\u65b9\u6cd5\u53ef\u4ee5\u5224\u65ad\u6570\u7ec4\u7684\u6240\u6709\u5143\u7d20\u662f\u5426\u6ee1\u8db3\u6d4b\u8bd5\u6761\u4ef6<\/p>\n\n\n\n
find()<\/code>\u65b9\u6cd5\u7528\u4e8e\u67e5\u627e\u7b26\u5408\u6761\u4ef6\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\uff0c\u5982\u679c\u627e\u5230\u4e86\uff0c\u8fd4\u56de\u8fd9\u4e2a\u5143\u7d20\uff0c\u5426\u5219\uff0c\u8fd4\u56deundefined<\/code><\/p>\n\n\n\n
findIndex()<\/code>\u548cfind()<\/code>\u7c7b\u4f3c\uff0c\u4e5f\u662f\u67e5\u627e\u7b26\u5408\u6761\u4ef6\u7684\u7b2c\u4e00\u4e2a\u5143\u7d20\uff0c\u4e0d\u540c\u4e4b\u5904\u5728\u4e8efindIndex()<\/code>\u4f1a\u8fd4\u56de\u8fd9\u4e2a\u5143\u7d20\u7684\u7d22\u5f15\uff0c\u5982\u679c\u6ca1\u6709\u627e\u5230\uff0c\u8fd4\u56de-1<\/code><\/p>\n\n\n\n
forEach()<\/code>\u548cmap()<\/code>\u7c7b\u4f3c\uff0c\u5b83\u4e5f\u628a\u6bcf\u4e2a\u5143\u7d20\u4f9d\u6b21\u4f5c\u7528\u4e8e\u4f20\u5165\u7684\u51fd\u6570\uff0c\u4f46\u4e0d\u4f1a\u8fd4\u56de\u65b0\u7684\u6570\u7ec4\u3002forEach()<\/code>\u5e38\u7528\u4e8e\u904d\u5386\u6570\u7ec4\uff0c\u56e0\u6b64\uff0c\u4f20\u5165\u7684\u51fd\u6570\u4e0d\u9700\u8981\u8fd4\u56de\u503c\uff1a<\/p>\n\n\n\n
let arr = [‘Apple’, ‘pear’, ‘orange’];
arr.forEach(x=>console.log(x)); \/\/ \u4f9d\u6b21\u6253\u5370\u6bcf\u4e2a\u5143\u7d20<\/p>\n\n\n\n
\u9ad8\u9636\u51fd\u6570\u9664\u4e86\u53ef\u4ee5\u63a5\u53d7\u51fd\u6570\u4f5c\u4e3a\u53c2\u6570\u5916\uff0c\u8fd8\u53ef\u4ee5\u628a\u51fd\u6570\u4f5c\u4e3a\u7ed3\u679c\u503c\u8fd4\u56de<\/p>\n\n\n\n
\u7bad\u5934\u51fd\u6570<\/p>\n\n\n\n
\nx => x * x<\/code><\/pre>\n\n\n\n
\u4e0a\u9762\u7684\u7bad\u5934\u51fd\u6570\u76f8\u5f53\u4e8e\uff1a<\/p>\n\n\n\n
function (x) {\n    return x * x;\n}\n<\/code><\/pre>\n\n\n\n
\u8fd8\u6709\u4e00\u79cd\u53ef\u4ee5\u5305\u542b\u591a\u6761\u8bed\u53e5\uff0c\u8fd9\u65f6\u5019\u5c31\u4e0d\u80fd\u7701\u7565{ ... }<\/code>\u548creturn<\/code>\uff1a<\/p>\n\n\n\n
x => {\n    if (x > 0) {\n        return x * x;\n    }\n    else {\n        return - x * x;\n    }\n}\n<\/code><\/pre>\n\n\n\n
\u5982\u679c\u53c2\u6570\u4e0d\u662f\u4e00\u4e2a\uff0c\u5c31\u9700\u8981\u7528\u62ec\u53f7()<\/code>\u62ec\u8d77\u6765<\/p>\n\n\n\n
\u6807\u7b7e\u51fd\u6570<\/p>\n\n\n\n
const email = “test@example.com”;
const password = ‘hello123’;<\/p>\n\n\n\n
function sql(strings, \u2026exps) {
console.log(SQL: ${strings.join('?')}<\/code>);
console.log(SQL parameters: ${JSON.stringify(exps)}<\/code>);
return {
name: ‘\u5c0f\u660e’,
age: 20
};
}<\/p>\n\n\n\n
const result = sqlSELECT * FROM users WHERE email=${email} AND password=${password}<\/code>;<\/p>\n\n\n\n
console.log(JSON.stringify(result));<\/p>\n\n\n\n
\u8fd9\u91cc\u51fa\u73b0\u4e86\u4e00\u4e2a\u5947\u602a\u7684\u8bed\u6cd5\uff1a<\/p>\n\n\n\n
sql`SELECT * FROM users WHERE email=${email} AND password=${password}`\n<\/code><\/pre>\n\n\n\n
\u6a21\u677f\u5b57\u7b26\u4e32\u524d\u9762\u4ee5sql<\/code>\u5f00\u5934\uff0c\u5b9e\u9645\u4e0a\u8fd9\u662f\u4e00\u4e2a\u6807\u7b7e\u51fd\u6570\uff0c\u4e0a\u8ff0\u8bed\u6cd5\u4f1a\u81ea\u52a8\u8f6c\u6362\u4e3a\u5bf9sql()<\/code>\u51fd\u6570\u7684\u8c03\u7528\u3002\u6211\u4eec\u5173\u6ce8\u7684\u662f\uff0c\u4f20\u5165sql()<\/code>\u51fd\u6570\u7684\u53c2\u6570\u662f\u4ec0\u4e48\u3002<\/p>\n\n\n\n
sql()<\/code>\u51fd\u6570\u5b9e\u9645\u4e0a\u63a5\u6536\u4e24\u4e2a\u53c2\u6570\uff1a<\/p>\n\n\n\n
\u7b2c\u4e00\u4e2a\u53c2\u6570strings<\/code>\u662f\u4e00\u4e2a\u5b57\u7b26\u4e32\u6570\u7ec4\uff0c\u5b83\u662f[\"SELECT * FROM users WHERE email=\", \" AND password=\", \"\"]<\/code>\uff0c\u5373\u9664\u53bb${xxx}<\/code>\u5269\u4e0b\u7684\u5b57\u7b26\u7ec4\u6210\u7684\u6570\u7ec4\uff1b<\/p>\n\n\n\n
\u7b2c\u4e8c\u4e2a\u53c2\u6570...exps<\/code>\u662f\u4e00\u4e2a\u53ef\u53d8\u53c2\u6570\uff0c\u5b83\u63a5\u6536\u7684\u4e5f\u662f\u4e00\u4e2a\u6570\u7ec4\uff0c\u4f46\u6570\u7ec4\u7684\u5185\u5bb9\u662f\u7531\u6a21\u677f\u5b57\u7b26\u4e32\u91cc\u6240\u6709\u7684${xxx}<\/code>\u7684\u5b9e\u9645\u503c\u7ec4\u6210\uff0c\u5373[\"test@example.com\", \"hello123\"]<\/code>\uff0c\u56e0\u4e3a\u89e3\u6790${email}<\/code>\u5f97\u5230\"test@example.com\"<\/code>\uff0c\u89e3\u6790${password}<\/code>\u5f97\u5230\"hello123\"<\/code>\u3002<\/p>\n\n\n\n
\u751f\u6210\u5668     generator\u7531function*<\/code>\u5b9a\u4e49\uff08\u6ce8\u610f\u591a\u51fa\u7684*<\/code>\u53f7\uff09<\/p>\n\n\n\n
\u8c03\u7528generator\u5bf9\u8c61\u6709\u4e24\u4e2a\u65b9\u6cd5\uff0c\u4e00\u662f\u4e0d\u65ad\u5730\u8c03\u7528generator\u5bf9\u8c61\u7684next()<\/code>\u65b9\u6cd5<\/p>\n\n\n\n
\u7b2c\u4e8c\u4e2a\u65b9\u6cd5\u662f\u76f4\u63a5\u7528for ... of<\/code>\u5faa\u73af\u8fed\u4ee3generator\u5bf9\u8c61<\/p>\n\n\n\n
function* fib(max) {\n    let\n        a = 0,\n        b = 1,\n        n = 0;\n    while (n < max) {\n        yield a;\n        [a, b] = [b, a + b];\n        n ++;\n    }\n    return;\n}\n\nfor (let x of fib(10)) {\n    console.log(x); \/\/ \u4f9d\u6b21\u8f93\u51fa0, 1, 1, 2, 3, ...\n}<\/code><\/pre>\n\n\n\n
\u5728JavaScript\u4e2d\uff0cDate<\/code>\u5bf9\u8c61\u7528\u6765\u8868\u793a\u65e5\u671f\u548c\u65f6\u95f4\u3002<\/p>\n\n\n\n
\u8981\u83b7\u53d6\u7cfb\u7edf\u5f53\u524d\u65f6\u95f4\uff0c\u7528\uff1a<\/p>\n\n\n\n
let now = new Date();\nnow; \/\/ Wed Jun 24 2015 19:49:22 GMT+0800 (CST)\nnow.getFullYear(); \/\/ 2015, \u5e74\u4efd\nnow.getMonth(); \/\/ 5, \u6708\u4efd\uff0c\u6ce8\u610f\u6708\u4efd\u8303\u56f4\u662f0~11\uff0c5\u8868\u793a\u516d\u6708\nnow.getDate(); \/\/ 24, \u8868\u793a24\u53f7\nnow.getDay(); \/\/ 3, \u8868\u793a\u661f\u671f\u4e09\nnow.getHours()<\/code><\/pre>\n\n\n\n
JavaScript\u6709\u4e24\u79cd\u65b9\u5f0f\u521b\u5efa\u4e00\u4e2a\u6b63\u5219\u8868\u8fbe\u5f0f\uff1a<\/p>\n\n\n\n
\u7b2c\u4e00\u79cd\u65b9\u5f0f\u662f\u76f4\u63a5\u901a\u8fc7\/\u6b63\u5219\u8868\u8fbe\u5f0f\/<\/code>\u5199\u51fa\u6765\uff0c\u7b2c\u4e8c\u79cd\u65b9\u5f0f\u662f\u901a\u8fc7new RegExp('\u6b63\u5219\u8868\u8fbe\u5f0f')<\/code>\u521b\u5efa\u4e00\u4e2aRegExp\u5bf9\u8c61\u3002<\/p>\n\n\n\n
\u4e24\u79cd\u5199\u6cd5\u662f\u4e00\u6837\u7684\uff1a<\/p>\n\n\n\n
let re1 = \/ABC\\-001\/;\nlet re2 = new RegExp('ABC\\\\-001');\n\nre1; \/\/ \/ABC\\-001\/\nre2; \/\/ \/ABC\\-001\/\n<\/code><\/pre>\n\n\n\n
\u6ce8\u610f\uff0c\u5982\u679c\u4f7f\u7528\u7b2c\u4e8c\u79cd\u5199\u6cd5\uff0c\u56e0\u4e3a\u5b57\u7b26\u4e32\u7684\u8f6c\u4e49\u95ee\u9898\uff0c\u5b57\u7b26\u4e32\u7684\u4e24\u4e2a\\\\<\/code>\u5b9e\u9645\u4e0a\u662f\u4e00\u4e2a\\<\/code>\u3002<\/p>\n\n\n\n
\u5148\u770b\u770b\u5982\u4f55\u5224\u65ad\u6b63\u5219\u8868\u8fbe\u5f0f\u662f\u5426\u5339\u914d\uff1a<\/p>\n\n\n\n
let re = \/^\\d{3}\\-\\d{3,8}$\/;\nre.test('010-12345'); \/\/ true\nre.test('010-1234x'); \/\/ false\nre.test('010 12345'); \/\/ false\n<\/code><\/pre>\n\n\n\n
RegExp\u5bf9\u8c61\u7684test()<\/code>\u65b9\u6cd5\u7528\u4e8e\u6d4b\u8bd5\u7ed9\u5b9a\u7684\u5b57\u7b26\u4e32\u662f\u5426\u7b26\u5408\u6761\u4ef6<\/p>\n\n\n\n
JSON\u662fJavaScript Object Notation\u7684\u7f29\u5199\uff0c\u5b83\u662f\u4e00\u79cd\u6570\u636e\u4ea4\u6362\u683c\u5f0f,JSON\u5b9e\u9645\u4e0a\u662fJavaScript\u7684\u4e00\u4e2a\u5b50\u96c6\u3002\u5728JSON\u4e2d\uff0c\u4e00\u5171\u5c31\u8fd9\u4e48\u51e0\u79cd\u6570\u636e\u7c7b\u578b\uff1a<\/p>\n\n\n\n