function map(f, a) { const result = new Array(a.length); for (let i = 0; i < a.length; i++) { result[i] = f(a[i]); } return result; } 在以下代码中,该函数接收由函数表达式定义的函数,并对作为第二个参数接收的数组的每个元素执行该函数: jsCopy to Clipboard function map(f,...
js constformatArg=(arg)=>{if(Array.isArray(arg)){// 打印一个无序列表returnarg.map((part)=>`-${part}`).join("\n");}if(arg.toString===Object.prototype.toString){// 这个对象会被序列化为“[object Object]”。// 我们来打印更漂亮的东西。returnJSON.stringify(arg);}returnarg;};constpr...
console.log(ary2.next());//Object {value: Array[2], done: false} value:Array[2] ---[0:0,1:1]; console.log(ary2.next());//Object {value: Array[2], done: false} value:Array[2] ---[0:1,1:2]; //可以看出每次执行这个next().都会返回一个该数组的索引和值组成的新的数组,被...
Learn about the StyleSheetList interface, including its properties and methods, code examples, specifications, and browser compatibility.
array.every(function(Value,index,arr),obj) 该函数接受五个参数第一个function,返回boolea值,就是通过every方法里面函数进行去判断,所以function是必须的, 第二个参数就是Value,当前数组循环比较的每一项值,第三个index就是该值对应的索引,第四个arr就是当前元素所在的数组,第五个参数就是可以改变function关键字...
$ mdn array#Methods Opens theArraydocumentation on MDN in your browser and jumps down to theMethodssection. Compatability mdnusesopenwhich tries to find a suitable command for opening URLs in your browser, regardless of which platform you're on. If you're having problems usingmdnon your platfo...
js // Legacy array comprehensions[for(xofiterable)x][for(xofiterable)if(condition)x][for(xofiterable)for(yofiterable)x+y]// Legacy generator comprehensions(for(xofiterable)x)(for(xofiterable)if(condition)x)(for(xofiterable)for(yofiterable)x+y) ...
Learn about the HTMLCollection interface, including its properties and methods, specifications and browser compatibility.
Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, using bracket notation). 311 WeakMap WeakMap对象就是简单的键/值映射.但键只能是对象值,不可以是原始值. 312 WeakMap.prototype.delete() delete() 方法可以从...
Methods Promise.all(iterable) Returns a promise that either fulfills when all of the promises in the iterable argument have fulfilled or rejects as soon as one of the promises in the iterable argument rejects. If the returned promise fulfills, it is fulfilled with an array of the values from...