To create JavaScriptuniquearray, we can make use of theSetconstructor and the higher-orderfiltermethod. For theSetconstructor, we will make use of thespreadoperator to create a new array that contains only unique elements. However, for thefiltermethod, we need to create a test using theindex...
1. slice() constnewAry = ary.slice() 2. concat constnewAry = [].concat(ary) 3. spread opreator: constnewAry = [...ary] 4. Array.from: constnewAry = Array.from(ary) Object: Shadow copy: 1. object.assign: constnewObj = Object.assign({}, obj, {prop:'newProp'}) 2. spread ...
y);// calling function `foo` with parameters `x` and `y`obj.bar(3);// calling method `bar` of object `obj`// A conditional statementif(x===0){// Is `x` equal to zero?x=123;}// Defining function `baz` with parameters `a` and ...
// empty array const emptyArray = []; // array of strings const dailyActivities = ["eat", "work", "sleep"]; // array with mixed data types const mixedArray = ["work", 1, true]; Note: Unlike many other programming languages, JavaScript allows us to create arrays with mixed data ...
原生对象(Native Objects):可以由用户通过 Array、RegExp 等内置构造器或者特殊语法创建的对象。 JavaScript 中,能够通过语言本身的构造器创建的对象称为原生对象。在 JavaScript 中,提供了 30 多个构造器。下面按照 winter 老师的理解,按照不同应用场景,把原生对象分为了一下几个种类。
constmerged=newMap([...first,...second,[1,"eins"]]);console.log(merged.get(1));// einsconsole.log(merged.get(2));// dosconsole.log(merged.get(3));// three 规范 Specification ECMAScript® 2026 Language Specification #sec-map-objects...
import { Serializer } from 'example-library';/*** An interface describing a widget.* @public*/export interface IWidget {/*** Draws the widget on the display surface.* @param x - the X position of the widget* @param y - the Y position of the widget*/public draw(x: number, y: ...
(val, idx, array) { console.log(val + " -> " + obj[val]); }); // 输出 // 0 -> a // 1 -> b // 2 -> c //不可枚举属性 var my_obj = Object.create({}, { getFoo: { value: function() { return this.foo; }, enumerable: false } }); my_obj.foo = 1; console....
警告:修改任何内置构造函数的prototype属性被认为是一种不好的做法,可能会影响向前兼容性。 你可以阅读更多关于原型的内容,参见继承与原型链。 规范 Specification ECMAScript® 2026 Language Specification #sec-object-objects
这也就意味着,变量名 test 和变量名 Test 分别表示两个不同的变量,而函数名不能使用 typeof,因它是一个关键字(3.2 节介绍关键字),但 typeOf 则完全可以是一个有效的函数名。 标志符 所谓标识符,就是指变量、函数、属性的名字,或者函数的参数。标识符可以是按照下列格式规则 组合起来的一或多个字符: 第一...