JS标准库的部分内置对象的常用属性和方法

摘要：常用的属性和方法创建空创建给对象添加属性给对象添加多个属性给对象添加给对象添加返回属性配置对象返回所有属性名数组返回对象原型对象阻止对象扩展冻结对象密封对象检测是否可扩展布尔值检测是否冻结布尔值检测是否密封布尔值对象原型对象对象实例的属性和

var o1 = {};
var o2 = Object.create(Object.prototype);

var o3 = {
    str: "string...",
    fun: function() {
        return this.str;
    }
};

Object.defineProperty(o1, "newPropertyName", { value: "str", enumerable: true, writable: true });

Object.defineProperties(o1, {
    newPropertyName1: { value: "str1", writable: false },
    newPropertyName2: { value: "str2", writable: true }
});

Object.defineProperty(o1, "logIt", {
    get: function () {
        return this.newPropertyName;
    }
});

Object.defineProperty(o1, "renew", {
    set: function (newValue) {
        this.newPropertyName = newValue;
    }
});

Object.getOwnPropertyDescriptor(o1, "newPropertyName");

Object.getOwnPropertyNames(o1);

Object.getPrototypeOf(o1);

Object.preventExtensions(o1);

Object.freeze(o1);

Object.seal(o1);

Object.isExtensible(o1);

Object.isFrozen(o1);

Object.isSealed(o1);

o1.constructor;

o1.hasOwnProperty("newPropertyName");

o1.isPrototypeOf(o1);

o1.propertyIsEnumerable("newPropertyName");

o1.toString();

o1.valueOf();

var arr = [1,2,3,4,5];

Array.length;

Array.prototype;

Array.isArray();

arr.constructor;

arr.length;

Mutator方法

以下方法改变原数组

arr.pop();
arr.push("end");
arr.shift();
arr.unshift("start");

arr.splice(1, 3); //从第二个开始，删除三个元素
arr.splice(1, 0, "newing","anotherNewing"); //从第二个开始，删除零个，添加两个新元素

arr.reverse();

arr.sort();

Accessor方法

以下方法不改变原数组

var newArr = arr.concat("newArrayItem");

var newArr = arr.slice(1, 3); //抽取从第二个元素开始到第四个元素（不包括第四个）结束成新数组

var string = arr.join("-");

var string = arr.toString();

var index = arr.indexOf("end");

var index = arr.indexOf("end");

Accessor方法

以下方法不改变原数组

arr.forEach(function (currentValue, index, array) {
    //body...
});

var result = arr.every(function (currentValue, index, array) {
    return typeof currentValue === "string";
});

var result = arr.some(function (currentValue, index, array) {
    return currentValue.length === 3;
});

var newArray = arr.filter(function (currentValue, index, array) {
    return currentValue.length === 3;
});

var newArray = arr.map(function (currentValue, index, array) {
    return currentValue + "[string...]";
});

var result = arr.reduce(function (previousValue, currentValue, index, array) {
    return previousValue + " " + currentValue;
}, "beginDoingThis"); //第二参数为初始值

var result = arr.reduceRight(function (previousValue, currentValue, index, array) {
    return previousValue + " " + currentValue;
}, "beginDoingThis"); //第二参数为初始值

function add(x, y) {
    return arguments;
}

add.length;

add.name;

add.call(null, 1, 2, 3);

add.apply(null, [1, 2, 3]);

var anotherAdd = add.bind(null, 1, 2);

add.toString();

var s1 = "string...";
var s2 = String("hello there good morning...");

String.prototype

var str = String.fromCharCode(65, 66, 67);

var uniq = String.prototype.charCodeAt.call(s1, 0);

s1.constructor;

s1.length;

s1.trim();

string和unicode转化和索引

s1.charAt("0");

s1.charCodeAt(0);

s1.indexOf("searchString", 0); //第二个参数为开始的位置

s1.lastIndexOf("searchString", 0); //第二个参数为开始的位置

创建子字符串或数组的方法

var str = s1.substring(-3,s1.length); //接收正整数（负数转化为0）

var str = s1.substr(3,2); //可接收负数（从右往左），第二个参数是期望字符串长度

var str = s1.slice(-3, 10); //可接收负数（length-数值）

var arr = s2.split(" ", 2); //以空格为分隔符最多切割两次

正则相关的方法

var arr = s1.match(/str/g);

var newstr = s1.replace(/.{3}/, "!!!");

var index = s1.search(/str/g);

var r1 = new RegExp(/hello/ig);
var r2 = /w{10}/;

RegExp.prototype

RegExp.length

r1.constructor;

r1.global
r1.ignoreCase
r1.multiline

r1.lastIndex;

r1.lastIndex = 0;

r1.exec("hello there, hello world");

r1.test("hello there");