18个编写JavaScript代码的技巧
web前端开发
共 3842字,需浏览 8分钟
·
2020-12-31 19:48
1、对常量使用“ const”而不是“ var”
/* Wrong */
var i = 1;
/* Correct */
const i = 1;
2、对更改的变量使用“ let”代替“ var”
/* Wrong */
var myVal = 1;
for (var i; i < 10; i++){
myVal = 1 + i;
}
/* Correct */
let myVal = 1;
for (let i; i < 10; i++){
myVal += i
}
3、声明对象
/* Wrong */
const myObject = new Object();
/* Correct */
const myObject = {};
4、声明数组
/* Wrong */
const myArray = new Array();
/* Correct */
const myArray = [];
5、连接字符串
/* Wrong */
const myStringToAdd = "world";
const myString = "hello " + myStringToAdd;
/* Correct */
const myStringToAdd = "world";
const myString = `hello ${myStringToAdd}`;
6、使用对象方法的简写
/* Wrong */
const customObject = {
val: 1,
addVal: function () {
return customObject.val + 1;
}
}
/* Correct */
const customObject = {
val: 1,
addVal(){
return customObject.val++
}
}
7、创建对象的值
/* Wrong */
const value = 1;
const myObject = {
value: value
}
/* Correct */
const value = 1;
const myObject = {
value
}
8、为对象分配值
/* Wrong */
const object1 = { val: 1, b: 2 };
let object2 = { d: 3, z: 4 };
object2.val = object1.val;
object2.b = object1.b;
/* Correct */
const object1 = { val: 1, b: 2 };
const object2 = { ...object1, d: 3, z: 4 }
9、给数组赋值
/* Wrong */
const myArray = [];
myArray[myArray.length] = "hello world";
/* Correct */
const myArray = [];
myArray.push('Hello world');
10、串联数组
/* Wrong */
const array1 = [1,2,3,4];
const array2 = [5,6,7,8];
const array3 = array1.concat(array2);
/* Correct */
const array1 = [1,2,3,4];
const array2 = [5,6,7,8];
const array3 = [...array1, ...array2]
11、获取对象的多个属性
/* Wrong */
function getFullName(client){
return `${client.name} ${client.last_name}`;
}
/* Correct */
function getFullName({name, last_name}){
return `${name} ${last_name}`;
}
12、从对象获取值
/* Wrong */
const object1 = { a: 1 , b: 2 };
const a = object1.a;
const b = object1.b;
/* Correct */
const object1 = { a: 1 , b: 2 };
const { a, b } = object1;
13、创建功能
/* Wrong */
function myFunc() {}
/* Wrong */
const myFunc = function() {}
/* Correct */
const myFunct = () => {}
14、默认值
/* Wrong */
const myFunct = (a, b) => {
if (!a) a = 1;
if (!b) b = 1;
return { a, b };
}
/* Correct */
const myFunct = (a = 1, b = 1) => {
return { a, b };
}
15、用“ reduce”代替“ forEach”和“ for”来求和
/* Wrong */
const values = [1, 2, 3, 4, 5];
let total = 0;
values.forEach( (n) => { total += n})
/* Wrong */
const values = [1, 2, 3, 4, 5];
let total = 0;
for (let i; i < values.length; i++){
total += values[i];
}
/* Correct */
const values = [1, 2, 3, 4, 5];
const total = values.reduce((total, num) => total + num);
16、存在于数组中
/* Wrong */
const myArray = [{a: 1}, {a: 2}, {a: 3}];
let exist = false;
myArray.forEach( item => {
if (item.a === 2) exist = true
})
/* Correct */
const myArray = [{a: 1}, {a: 2}, {a: 3}];
const exist = myArray.some( item => item.a == 2)
17、布尔值的快捷方式
/* Wrong */
const a = 1;
const b = 1;
let isTrue = false
if (a === b) {
isTrue = true
}
/* Correct */
const a = 1;
const b = 1;
const isTrue = a === b
18、值的快捷方式
/* Wrong */
const a = 5;
let b;
if (a === 5){
b = 3;
} else {
b = 2;
}
/* Correct */
const a = 5;
const b = a === 5 ? 3 : 2;
结论
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