FE.ES-(for...of) 可迭代对象Range(n) in JS

可迭代对象Array [10, 20, 30]String “boo"TypedArrayc new Uint8Array([0x00, 0xff])Map new Map([[“a”, 1], [“b”, 2], [“c”, 3]])Set new Set([1, 1, 2, 2, 3, 3])arguments (function() {for (let arg of arguments) console.log(arg)})(1, 2, 3)Nodelist document.querySelectorAll(“article > p”)（ 浏览器需支持 Nodelist [Symbol.iterator] ）[注意]document.getElementById 返回一个实时的 NodeListdocument.querySelectorAll 返回一个静态的 NodeListfor…offor…of语句在可迭代对象上创建一个迭代循环，调用自定义迭代钩子，并为每个不同属性的值执行语句。for…of还可以迭代生成器，生成器不应该重用。for…of与for…in的区别for…in 语句以原始插入顺序迭代对象的可枚举属性。for…of 语句遍历可迭代对象定义要迭代的数据。Object.prototype.objCustom = function() {}Array.prototype.arrCustom = function() {}let iterable = [3, 5, 7]iterable.foo = ‘hello’for (let i in iterable){ console.log(i) // logs 0, 1, 2, “foo”, “arrCustom”, “objCustom” if (iterable.hasOwnProperty(i)) console.log(i) // logs 0, 1, 2, “foo”}for (let i of iterable) console.log(i) // logs 3, 5, 7终止迭代break,return throw[注意] Array.forEach 不能 breakRange(n) in JShttps://stackoverflow.com/que…Numbers[…Array(5).keys()]; => [0, 1, 2, 3, 4]Character iterationString.fromCharCode( …[…Array(‘D’.charCodeAt(0) - ‘A’.charCodeAt(0) + 1).keys()] .map(i => i + ‘A’.charCodeAt(0))); => “ABCD"Iterationfor (const x of Array(5).keys()) { console.log(x, String.fromCharCode(‘A’.charCodeAt(0) + x));} => 0,“A” 1,“B” 2,“C” 3,“D” 4,“E"As functionsfunction range(size, startAt = 0) { return […Array(size).keys()].map(i => i + startAt);}function characterRange(startChar, endChar) { return String.fromCharCode(…range(endChar.charCodeAt(0) - startChar.charCodeAt(0), startChar.charCodeAt(0)))}As typed functionsfunction range(size:number, startAt:number = 0):ReadonlyArray<number> { return […Array(size).keys()].map(i => i + startAt);}function characterRange(startChar:string, endChar:string):ReadonlyArray<string> { return String.fromCharCode(…range(endChar.charCodeAt(0) - startChar.charCodeAt(0), startChar.charCodeAt(0)))}lodash.js .range() function.range(10); => [0, 1, 2, 3, 4, 5, 6, 7, 8, 9].range(1, 11); => [1, 2, 3, 4, 5, 6, 7, 8, 9, 10].range(0, 30, 5); => [0, 5, 10, 15, 20, 25].range(0, -10, -1); => [0, -1, -2, -3, -4, -5, -6, -7, -8, -9]String.fromCharCode(….range(‘A’.charCodeAt(0), ‘D’.charCodeAt(0) + 1)); => “ABCD"Old non es6 browsers without a library:Array.apply(null, Array(5)).map(function (_, i) {return i;}); => [0, 1, 2, 3, 4]console.log([…Array(5).keys()]);