nestedArray[2][1][0][0][0] ='deeper still';console.log(nestedArray[2][1][0][0][0]);// 现在输出:deeper still letmyNestedArray = [ ['unshift',false,1,2,3,'complex','nested'], ['loop','shift',6,7,1000,'method'], ['concat',false,true,'spread','array',['deep']], [...
Spread Operator 则与 Rest Opeator 的功能正好相反,其常用于进行数组构建与解构赋值,也可以用于将某个数组转化为函数的参数列表,其基本使用方式如下: let cold = ['autumn', 'winter']; let warm = ['spring', 'summer']; // construct an array [...cold, ...warm] // => ['autumn', 'winter',...
let o = { // An object o.m: function() { // Method m of the object.let self = this; // Save the "this" value in a variable.this === o // => true: "this" is the object o.f(); // Now call the helper function f().function f() { // A nested function fthis ===...
46 You can also use the spread operator to expand the string into the array of characters, clone the string, or concatenate the string. Also, set, map, etc., are iterable objects in JavaScript. So, you can use the spread operator with them. ...
constmyMap=newMap();myMap.set(1,'apple');myMap.set(2,'banana');myMap.set(3,'cherry');document.write(myMap.delete(2),"");//truedocument.write(myMap.has(2));//false The above program removes the key-value pair associated with the key '2' from the Map object. Print Page Previ...
objects (default: true)— compact duplicate keys in object literals. passes (default: 1)— The maximum number of times to run compress. In some cases more than one pass leads to further compressed code. Keep in mind more passes will take more time. properties (default: true)— rewrite pro...
first, but if you're familiar with JavaScript, you know that this can be extermely useful to the programmer, especially when dealing with nested functions, which are a bit syntactically awkward in Python (it's not immediatelly obvious that those can be copied and assigned to other objects)...
Plainobjects: {firstName:'Jane',lastName:'Doe'} Arrays: ['apple','banana','cherry'] Here are a few examplesof basic syntax: // Two slashes start single-linecommentsvarx;// declaring a variablex=3+y;// assigning a value to the variable `x`foo(x,y);// calling function `foo` wit...
Objects => true Undefined => false Null => false Booleans => the value of the boolean Numbers +0, -0, or NaN => false 其他=> true Strings '' => false 其他=> true if ([0] && []) { // true // 数组(即使是空数组)是对象,对象会计算成 true } ...
Objects 3.1Use the literal syntax for object creation. eslint:no-new-object // badconstitem =newObject();// goodconstitem = {}; 3.2Use computed property names when creating objects with dynamic property names. Why? They allow you to define all the properties of an object in one place. ...