Explication détaillée des méthodes d'extension d'objet Array et d'extension d'objet String dans JS

Cet article présente principalement les informations pertinentes sur l'explication détaillée de l'Extension de l'objet Array et de l'expansion de l'objet String dans JS. Les amis qui en ont besoin peuvent s'y référer

Plus de bêtises, je. vous le donnera directement. Le code d'expansion de l'objet tableau est affiché ci-dessus. Le code spécifique est le suivant :

/**
* Created by laixiangran on 2016/01/07.
* Array扩展
*/
(function() {
// 遍历数组
if (typeof Array.prototype.forEach != "function") {
Array.prototype.forEach = function (fn, context) {
for (var i = 0; i < this.length; i++) {
if (typeof fn === "function" && Object.prototype.hasOwnProperty.call(this, i)) {
fn.call(context, this[i], i, this);
}
}
};
}
// 让数组中的每一个元素调用给定的函数，然后把得到的结果放到新数组中返回
if (typeof Array.prototype.map != "function") {
Array.prototype.map = function (fn, context) {
var arr = [];
if (typeof fn === "function") {
for (var k = 0, length = this.length; k < length; k++) {
arr.push(fn.call(context, this[k], k, this));
}
}
return arr;
};
}
// 把符合条件的元素放到一个新数组中返回
if (typeof Array.prototype.filter != "function") {
Array.prototype.filter = function (fn, context) {
var arr = [];
if (typeof fn === "function") {
for (var k = 0, length = this.length; k < length; k++) {
fn.call(context, this[k], k, this) && arr.push(this[k]);
}
}
return arr;
};
}
// 如果数组中的每个元素都能通过给定的函数的测试，则返回true，反之false
if (typeof Array.prototype.every != "function") {
Array.prototype.every = function (fn, context) {
var passed = true;
if (typeof fn === "function") {
for (var k = 0, length = this.length; k < length; k++) {
if (passed === false) break;
passed = !!fn.call(context, this[k], k, this);
}
}
return passed;
};
}
// 类似every函数，但只要有一个通过给定函数的测试就返回true
if (typeof Array.prototype.some != "function") {
Array.prototype.some = function (fn, context) {
var passed = false;
if (typeof fn === "function") {
for (var k = 0, length = this.length; k < length; k++) {
if (passed === true) break;
passed = !!fn.call(context, this[k], k, this);
}
}
return passed;
};
}
// 返回元素在数组的索引，没有则返回-1，从左到右
if (typeof Array.prototype.indexOf != "function") {
Array.prototype.indexOf = function (item, index) {
var n = this.length,
i = index == null ? 0 : index < 0 ? Math.max(0, n + index) : index;
for (; i < n; i++) {
if (i in this && this[i] === item) {
return i
}
}
return -1
};
}
// 返回元素在数组的索引，没有则返回-1，从右到左
if (typeof Array.prototype.lastIndexOf != "function") {
Array.prototype.lastIndexOf = function (item, index) {
var n = this.length,
i = index == null ? n-1 : index < 0 ? Math.max(0, n + index) : index;
for (; i >= 0; i--) {
if (i in this && this[i] === item) {
return i;
}
}
return -1;
};
}
// 让数组元素依次调用给定函数，最后返回一个值（从左到右）
if (typeof Array.prototype.reduce != "function") {
Array.prototype.reduce = function (callback, initialValue) {
var previous = initialValue, k = 0, length = this.length;
if (typeof initialValue === "undefined") {
previous = this[0];
k = 1;
}
if (typeof callback === "function") {
for (k; k < length; k++) {
this.hasOwnProperty(k) && (previous = callback(previous, this[k], k, this));
}
}
return previous;
};
}
// 让数组元素依次调用给定函数，最后返回一个值（从右到左）
if (typeof Array.prototype.reduceRight != "function") {
Array.prototype.reduceRight = function (callback, initialValue) {
var length = this.length, k = length - 1, previous = initialValue;
if (typeof initialValue === "undefined") {
previous = this[length - 1];
k--;
}
if (typeof callback === "function") {
for (k; k > -1; k-=1) {
this.hasOwnProperty(k) && (previous = callback(previous, this[k], k, this));
}
}
return previous;
};
}
// 去掉重复项（唯一性），返回新数组
if (typeof Array.prototype.uniq != "function") {
Array.prototype.uniq = function() {
var arr = [];
arr[0] = this[0];
for (var i = 1; i < this.length; i++) {
if (arr.indexOf(this[i]) == -1) {
arr.push(this[i]);
}
}
return arr;
};
}
// 指定删除数组中某值
if (typeof Array.prototype.remove != "function") {
Array.prototype.remove = function(item) {
for (var i = this.length; i >= 0; i--) {
if (item === this[i]) {
this.splice(i, 1);
}
}
return this;
};
}
// 打乱数组顺序
if (typeof Array.prototype.shuffle != "function") {
Array.prototype.shuffle = function() {
var i = this.length;
while (i) {
var j = Math.floor(Math.random()*i);
var t = this[--i];
this[i] = this[j];
this[j] = t;
}
return this;
};
}
// 求数组的最大值
if (typeof Array.prototype.max != "function") {
Array.prototype.max = function() {
return Math.max.apply({}, this)
};
}
// 求数组的最小值
if (typeof Array.prototype.max != "function") {
Array.prototype.min = function() {
return Math.min.apply({}, this)
};
} 

// 判断是否为数组
if (typeof Array.prototype.isArray != "function") {
Array.prototype.isArray = function() {
return Object.prototype.toString.apply(this) === "[object Array]";
};
} 
}());

Ce qui suit est le code d'expansion de l'objet chaîne comme suit :

/**
* Created by laixiangran on 2015/12/12.
* String扩展
*/
(function() {
// 十六进制颜色值的正则表达式
var reg = /^#([0-9a-fA-f]{3}|[0-9a-fA-f]{6})$/;
// RGB颜色转换为16进制
if (typeof String.prototype.rgbToHex != "function") {
String.prototype.rgbToHex = function() {
var that = this;
if (/^(rgb|RGB)/.test(that)) {
var aColor = that.replace(/(?:\(|\)|rgb|RGB)*/g,"").split(",");
var strHex = "#";
for (var i=0; i<aColor.length; i++) {
var hex = Number(aColor[i]).toString(16);
if (hex === "0") {
hex += hex;
}
strHex += hex;
}
if (strHex.length !== 7) {
strHex = that;
}
return strHex;
}else if (reg.test(that)) {
var aNum = that.replace(/#/,"").split("");
if (aNum.length === 6){
return that;
}else if (aNum.length === 3) {
var numHex = "#";
for (var j=0; j<aNum.length; j++) {
numHex += (aNum[j]+aNum[j]);
}
return numHex;
}
}else{
return that;
}
};
}
// 16进制颜色转为RGB格式
if (typeof String.prototype.hexToRgb != "function") {
String.prototype.hexToRgb = function() {
var sColor = this.toLowerCase();
if (sColor && reg.test(sColor)) {
if (sColor.length === 4) {
var sColorNew = "#";
for (var i = 1; i < 4; i++) {
sColorNew += sColor.slice(i,i+1).concat(sColor.slice(i,i+1));
}
sColor = sColorNew;
}
// 处理六位的颜色值
var sColorChange = [];
for (var j=1; j<7; j+=2) {
sColorChange.push(parseInt("0x"+sColor.slice(j,j+2)));
}
return "RGB(" + sColorChange.join(",") + ")";
}else{
return sColor;
}
};
}
// 移除字符串首尾空白
if (typeof String.prototype.trim != "function") {
String.prototype.trim = function() {
return this.replace(/^\s+|\s+$/g, "");
};
}
}());

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