随笔分类 - Javascript
摘要：It is not good to import axios from each Components or different services, because it will create a new instance of axios everytime. import axios from
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摘要：Main difference is that in keyword will check on object prototype chain as well but hasOwnProperty won't check agaist prototype chain const obj = {} '
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摘要：Let's see the following code function copyText(text) { if (navigator.clipboard) { navigator.clipboard.writeText(text); } else { const input = document
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摘要：The Reflect namespace object contains static methods for invoking interceptable JavaScript object internal methods. The methods are the same as those
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摘要：const [a, b] = { a: 3, b: 4, }; console.log(a, b); // TypeError: {(intermediate value)(intermediate value)} is not iterable How to make it work withou
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摘要：// loop function demo1() { // before loop beforeLoopCode; for (initCode; conditionCode; stepChangeCode) { loopCode } postCode } // recursive function
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摘要：class MemoizeMap { constructor() { this._map = new Map(); this._weakMap = new WeakMap(); } _isObject(v) { return typeof v "object" && v !== null; } se
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摘要：Promise.myAll = function (promises) { let res, rej; const p = new Promise((resolve, reject) => { res = resolve; rej = reject; }); let i = 0; let resul
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摘要：Function.apply.myCall = function (ctx, ...args) { ctx = ctx null || ctx undefined ? globalThis : Object(ctx); const fn = this; const key = Sybmol("fn"
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摘要：For Javascript Object, you cannot assume the order of Object property the same as the order of adding those property. The actual order follow this rul
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摘要：Proxy The Proxy object enables you to create a proxy for another object, which can intercept and redefine fundamental operations for that object. So w
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摘要：[] + [] Answer: "" Both arrays ([]) are first converted to their string representations before the + operator is applied. In JavaScript, arrays are co
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摘要：const obj = { a: 1, b: 2, c: { d: 1, e: 2, }, }; function isObject(val) { return val !== null && typeof val "object"; } function observe(obj) { const
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摘要：const obj = { a: 1, b: 2, c: { a: 1, b: 2, }, }; function isObject(val) { return val !== null && typeof val "object"; } function observe(obj) { for (l
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摘要：As we know we can read property value from an object as so: const obj = {} obj.xxxx; obj[xxxx]; So what's the difference between those two? obj.x ECMA
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摘要：Function.prototype.myBind = function (ctx, ...args) { const fn = this; return function (...subArgs) { console.log(new.target); const allArgs = [...arg
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摘要：The new.target meta-property lets you detect whether a function or constructor was called using the new operator. In constructors and functions invoke
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摘要：Eliminate the ambiguity of the function What ambiguity means? Normally a function can do two things 1. Instruction sequence 2. Contruction function a(
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摘要：async function asy1() { console.log(1) await asy2() console.log(2) } asy2 = async () => { // First set // await setTimeout((_) => { // Promise.resolve
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摘要：We often see circular dependency, why it's a problem, why we should avoid it and hwo to avoid it? Let's see any example first // main.js import A from
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