{if(hash[arr[i]]==undefined) hash[arr[i]]=1;//如果hash数组中arr[i]对应的元素未定义,说明未重复,则将其放入hash数组中}//结束遍历之后,取出hash数组varback=[];for(back[back.length]inhash);returnback; } console.log(f1([1,2,2,1,4,5])); 运行结果:["1","2","4","5"] 关于执行...
7-2.js class BendingUnit extends Robot { constructor(name, type){ super(name, type); } } } Listing 7-2Inheriating from a Parent Class Using the ES6 extends Keyword 这段代码使用extends关键字告诉环境,除了当前类中的特性之外,它还想使用来自父类的所有可用特性。因为您知道您想要使用父类的一些属...
slice() Selects part of an array and returns it as a new array. splice() Removes or replaces existing elements and/or adds new elements. To learn more, visit JavaScript Array Methods. More on Javascript Array Create an array using the new keyword. You can also create an array using...
constarray1=[1,2,3];constarray2=[4,5,6];constnewArray=array1.concat(array2);console.log(newArray);// 输出: [1, 2, 3, 4, 5, 6]console.log(array1);// 输出: [1, 2, 3],原始数组没有改变console.log(array2);// 输出: [4, 5, 6],原始数组没有改变 如上所示,通过调用concat(...
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,...
Javascript关键字（Keyword）是指在Javascript语言中有特定含义，成为Javascript语法中一部分的那些字，是 ...
We have an array of values. We specify the lower and upper bounds for the filtering in the context object. function isInRange(val) { return val >= this.lower && val <= this.upper; } We access the properties of the context via the this keyword. ...
a.push(1,2,3); // The push() method adds elements to an array a.reverse(); // Another method: reverse the order of elements // We can define our own methods, too. The "this" keyword refers to the object // on which the method is defined: in this case, the points array from...
Using an array literal is the easiest way to create a JavaScript Array. Syntax: It is a common practice to declare arrays with theconstkeyword. Learn more aboutconstwith arrays in the chapter:JS Array Const. Example constcars = ["Saab","Volvo","BMW"]; ...
What are the common errors in JavaScript? The common errors that developers make while coding in JavaScript include mistaken thinking about how the “this” keyword works, incorrect assumptions about block scoping, and a failure to avoid memory leaks. JavaScript’s evolution over time has left many...