18个编写JavaScript代码的技巧

/* Wrong */var i = 1;/* Correct */const i = 1;

/* 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}

/* Wrong */const myObject = new Object();/* Correct */const myObject = {};

/* Wrong */const myArray = new Array();/* Correct */const myArray = [];

/* Wrong */const myStringToAdd = "world";const myString = "hello " + myStringToAdd;/* Correct */const myStringToAdd = "world";const myString = `hello ${myStringToAdd}`;

/* Wrong */const customObject = {  val: 1,  addVal: function () {   return customObject.val + 1;  }}/* Correct */const customObject = {  val: 1,  addVal(){    return customObject.val++  }}

/* Wrong */const value = 1;const myObject = {  value: value}/* Correct */const value = 1;const myObject = {  value}

/* 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 }

/* Wrong */const myArray = [];myArray[myArray.length] = "hello world";/* Correct */const myArray = [];myArray.push('Hello world');

/* 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]

/* Wrong */function getFullName(client){  return `${client.name} ${client.last_name}`;}/* Correct */function getFullName({name, last_name}){  return `${name} ${last_name}`;}

/* 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;‍

/* Wrong */function myFunc() {}/* Wrong */const myFunc = function() {}/* Correct */const myFunct = () => {}

/* 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 };}

/* 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);

/* 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)

/* Wrong */const a = 1;const b = 1;let isTrue = falseif (a === b) {  isTrue = true}/* Correct */const a = 1;const b = 1;const isTrue = a === b

/* Wrong */const a = 5;let b;if (a === 5){  b = 3;} else {  b = 2;}/* Correct */const a = 5;const b = a === 5 ? 3 : 2;