18 good habits to write JavaScript!

Front end tips 2021-01-21 09:38:29
good habits write javascript


author :ivan.c
translator : The front end little wisdom
source :medium
Enjoy it , WeChat search The big move the world ,B Focus on The front end little wisdom This one doesn't have a big factory background , But people with an upward positive attitude . this paper GitHub https://github.com/qq44924588... I have included , The article has been classified , I've also compiled a lot of my documents , And tutorial materials .

Recently, we open source a Vue Components , It's not perfect , Welcome to improve it together , I hope you can give me a star support , Thank you .

github Address :https://github.com/qq44924588...

In my many years of programming , I'll give priority to the way I write code , Not just to make the code simpler , And because it helps to improve coding efficiency , Make code faster .

Write 1000 Line code and write 300 Lines of code are different , It's very helpful for the program or script we're working on . Programming must be very careful , Because in large projects , Dirty code can be a serious problem .

Many programmers criticize JS Language is not like Java or c++ That standard way of working , But the truth is JavaScript It's one of the best languages in use right now , Some of them are Facebook and Netflix. image React Such a library improves front-end performance , As for the back end ,nextJs Used to speed up , These combinations drive today's programmers crazy .

ECMAScript v6( Abbreviation for ES6 or ES2015) yes JavaScript since 2015 year 6 The standards that have been followed since January .

By learning the following skills , We can improve the way we write code . Take time to practice on the console , Study well .

Let's get started ~

1. Constant usage const Instead of var

A constant is a variable that never changes , Declaring variables in this way ensures that they never change .

/* The old way */
var i = 1;
/* The right way */
const i = 1;

2. Use let Replace variable , instead of var

let Statement Declares a local scope variable with block scope

/* Inappropriate */
var myVal = 1;
for (var i; i < 10; i++){
myVal = 1 + i;
}
/* The right way */
let myVal = 1;
for (let i; i < 10; i++){
myVal += i
}

3. Declare objects

Declare objects with shortcuts

/*
The old way
The Object() class makes an unnecessary function call
*/
const myObject = new Object();
/* The right way */
const myObject = {};

5. Connection string

/* The old way */
const myStringToAdd = "world";
const myString = "hello " + myStringToAdd;
/* The right way */
const myStringToAdd = "world";
const myString = `hello ${myStringToAdd}`;

6. Use the object method to abbreviate

/* Inappropriate */
const customObject = {
val: 1,
addVal: function () {
return customObject.val + 1;
}
}
/* The right way */
const customObject = {
val: 1,
addVal(){
return customObject.val++
}
}** Bold text **

7. Create the value of the object

/* The old way */
const value = 1;
const myObject = {
value: value
}
/* The right way */
const value = 1;
const myObject = {
value
}

8. Assign a value to an object

/* The old way */
const object1 = { val: 1, b: 2 };
let object2 = { d: 3, z: 4 };
object2.val = object1.val;
object2.b = object1.b;
/* The right way */
const object1 = { val: 1, b: 2 };
const object2 = { ...object1, d: 3, z: 4 }

9. Assign value to array

/* Inappropriate */
const myArray = [];
myArray[myArray.length] = "hello world";
/* The right way */
const myArray = [];
myArray.push('Hello world');

10. Linked array

/* Inappropriate */
const array1 = [1,2,3,4];
const array2 = [5,6,7,8];
const array3 = array1.concat(array2);
/* The right way */
const array1 = [1,2,3,4];
const array2 = [5,6,7,8];
const array3 = [...array1, ...array2]

11. Get multiple properties of an object

/* Inappropriate */
function getFullName(client){
return `${client.name} ${client.last_name}`;
}
/* The right way */
function getFullName({name, last_name}){
return `${name} ${last_name}`;
}

12. Get values from objects

/* Inappropriate */
const object1 = { a: 1 , b: 2 };
const a = object1.a;
const b = object1.b;
/* The right way */
const object1 = { a: 1 , b: 2 };
const { a, b } = object1;

13. Create a function

/* The old , But it's good */
function myFunc() {}
/* very good */
const myFunc = function() {}
/* best */
const myFunct = () => {}
// Important note : In some cases , It is not recommended to use these functions with arrows , To avoid reading errors 

14. The default value is

/* Inappropriate */
const myFunct = (a, b) => {
if (!a) a = 1;
if (!b) b = 1;
return { a, b };
}
/* The right way */
const myFunct = (a = 1, b = 1) => {
return { a, b };
}

15. Use reduce Instead of forEach and for Come and make peace

/* Inappropriate */
const values = [1, 2, 3, 4, 5];
let total = 0;
values.forEach( (n) => { total += n})
/* Inappropriate */
const values = [1, 2, 3, 4, 5];
let total = 0;
for (let i; i < values.length; i++){
total += values[i];
}
/* The right way */
const values = [1, 2, 3, 4, 5];
const total = values.reduce((total, num) => total + num);

16. Whether it exists in the array

/* Inappropriate */
const myArray = [{a: 1}, {a: 2}, {a: 3}];
let exist = false;
myArray.forEach( item => {
if (item.a === 2) exist = true
})
/* The right way */
const myArray = [{a: 1}, {a: 2}, {a: 3}];
const exist = myArray.some( item => item.a == 2)

17. Shortcut to Boolean values

/* Inappropriate */
const a = 5;
let b;
if (a === 5){
b = 3;
} else {
b = 2;
}
/* The right way */
const a = 5;
const b = a === 5 ? 3 : 2;

summary

Review this article , Practice and learn how to work in a cleaner way , Improve processing speed .

End ~, This is Xiaozhi , I'm going to do the dishes , See you next time !


Possible after code deployment BUG There's no way to know in real time , In order to solve these problems afterwards BUG, It took a lot of time log debugging , This way, I'd like to recommend an easy-to-use one for you BUG Monitoring tools Fundebug.

original text :https://medium.com/javascript...

communication

Articles are updated every week , You can search by wechat 「 The big move the world 」 First time reading and urging ( One or two articles earlier than blog ), this paper GitHub https://github.com/qq449245884/xiaozhi Included , I organized a lot of my documents , welcome Star And perfection , You can refer to the interview site review , Pay attention to official account. , The background to reply welfare , You can see the benefits , You'll see .

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