将会持续更新个人笔记
class 继承
class A {
constructor() {
this.x = 2;
}
print() {
console.log(this.x)
}
}
class B extends A {
// 实化例时constructor()会自动执行
constructor() {
super();
console.log('constructor')
console.log(this.x)
this.print();
}
write(){
console.log(this.x + 1)
}
}
let b = new B();
b.print()
b.write()
// constructor
// 2
// 2
// 2
// 3
闭包
function makeAdder(x) {
return function(y) {
return x + y;
};
}
var add5 = makeAdder(5);
var add10 = makeAdder(10);
console.log(add5(2)); // 7
console.log(add10(2)); // 12
解构赋值
let [a,b,c] = [1,2,3] //对应下标
let {a,b,c} = {a:1,b:2,c:3} //对应key
// 交换变量的值
let x = 1
let y = 2
[x,y] = [y,x]
拷贝
let a = [1,2,3]
//拷贝后更改a数组的值将不会影响b,c
let b = Array.from(a)
let c = [...a]
let aa = {
a:1,
b:2
};
let bb = {...aa}
遍历
//数组
let a = ['a', 'b']
for(let [i,v] of a.entries()){
console.log(i,v);
}
for(let i of a.keys()){
console.log(i);
}
//对象
let obj = {
a:1,
b:2
}
for(let [key,value] of Object.entries(obj)){
console.log(key,value);
}
async await
const animate = async () => {
await new Promise((resolve,reject) => {
setTimeout(() => {
this.readyshow = true;
console.log(1)
resolve();
}, 500)
});
await new Promise((resolve,reject) => {
setTimeout(() => {
this.readyshow = false;
console.log(2)
resolve();
}, 2000)
});
console.log(3)
}
animate();
Promise.all
var promise1 = Promise.resolve(3);
var promise2 = 42;
var promise3 = new Promise(function(resolve, reject) {
setTimeout(resolve, 100, 'foo');
});
Promise.all([promise1, promise2, promise3]).then(function(values) {
console.log(values);
});
数组排序
var values = [0,1,3,7,9,15];
values.sort(compare);
alert(values); //0,1,3,7,9,15
function compare (value1,value2){
return value2 - value1;
}
对象排序
var arr = [
{name:'zopp',age:0},
{name:'gpp',age:18},
{name:'yjj',age:8}
];
function compare(property){
return function(a,b){
var value1 = a[property];
var value2 = b[property];
return value1 - value2;
}
}
console.log(arr.sort(compare('age')))
检测浏览器语言
function getBrowserLanguage() {
return (navigator.language || navigator.browserLanguage).toLowerCase();
}
检测是否为移动端
Vue.prototype.$isMobile = function () {
var a = navigator.userAgent;
return a.indexOf("Android") != -1 || a.indexOf("iPhone") != -1 || a.indexOf("iPad") != -1;
}();
时间戳
timestampToTime(timestamp) {
var date = new Date(timestamp * 1000); //时间戳为10位需*1000，时间戳为13位的话不需乘1000
var Y = date.getFullYear() + '-';
var M = (date.getMonth() + 1 < 10 ? '0' + (date.getMonth() + 1) : date.getMonth() + 1) + '-';
var D = date.getDate() + ' ';
var h = date.getHours() + ':';
var m = date.getMinutes() + ':';
var s = date.getSeconds();
return Y + M + D + h + m + s;
}
unicode加密解密
// 转为unicode 编码
function encodeUnicode(str) {
var res = [];
for ( var i=0; i<str.length; i++ ) {
res[i] = ( "00" + str.charCodeAt(i).toString(16) ).slice(-4);
}
return "\\u" + res.join("\\u");
}
// 解码
function decodeUnicode(str) {
str = str.replace(/\\/g, "%");
return unescape(str);
}
加减乘除
//加
function floatAdd(arg1,arg2){
var r1,r2,m;
try{r1=arg1.toString().split(".")[1].length}catch(e){r1=0}
try{r2=arg2.toString().split(".")[1].length}catch(e){r2=0}
m=Math.pow(10,Math.max(r1,r2));
return (arg1*m+arg2*m)/m;
}
//减
function floatSub(arg1,arg2){
var r1,r2,m,n;
try{r1=arg1.toString().split(".")[1].length}catch(e){r1=0}
try{r2=arg2.toString().split(".")[1].length}catch(e){r2=0}
m=Math.pow(10,Math.max(r1,r2));
//动态控制精度长度
n=(r1>=r2)?r1:r2;
return ((arg1*m-arg2*m)/m).toFixed(n);
}
//乘
function floatMul(arg1,arg2) {
var m=0,s1=arg1.toString(),s2=arg2.toString();
try{m+=s1.split(".")[1].length}catch(e){}
try{m+=s2.split(".")[1].length}catch(e){}
return Number(s1.replace(".",""))*Number(s2.replace(".",""))/Math.pow(10,m);
}
//除
function floatDiv(arg1,arg2){
var t1=0,t2=0,r1,r2;
try{t1=arg1.toString().split(".")[1].length}catch(e){}
try{t2=arg2.toString().split(".")[1].length}catch(e){}
r1=Number(arg1.toString().replace(".",""));
r2=Number(arg2.toString().replace(".",""));
return (r1/r2)*Math.pow(10,t2-t1);
}
验证邮箱
// is Email
Vue.prototype.$isEmail = function (email) {
var re = /^([\w-]+(?:\.[\w-]+)*)@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$/i;
return re.test(email);
}
验证手机号
// is Phone num
Vue.prototype.$isPhoneNum = function (num) {
var re = /^(((13[0-9]{1})|(14[0-9]{1})|(17[0]{1})|(15[0-3]{1})|(15[5-9]{1})|(18[0-9]{1}))+\d{8})$/;
return re.test(num);
}
