Coding With Fun
Home Docker Django Node.js Articles FAQ

A must-have for programmers, the ten most commonly used code shorthand techniques in JavaScript


Jun 02, 2021 Article blog



To determine whether a programmer is a good programmer, look at the code he writes and you can know a thing or two, because the most important thing for a programmer is to write code.

 A must-have for programmers, the ten most commonly used code shorthand techniques in JavaScript1

Good programmers write code that is neat and regulated, and visually naturally has a sense of beauty. Good programmers adopt consistent shorthand rules, while poor programmers sometimes don't shorthand, sometimes shorthand.

 A must-have for programmers, the ten most commonly used code shorthand techniques in JavaScript2

Today w3cschool editor-in-chief I put together a list of 10 programmers commonly used code shorthand technology, so that your code book shorthand neat specification has a sense of beauty, let's learn about these codes!

1, object properties shorthand

If the property name is the same as the key name, you can use ES6:

const obj = { x:x, y:y };

Shorthand:

const obj = { x, y };

2, declare the variable shorthand method

let x; l et y; let z = 3;

Shorthand:

let x, y, z=3;

3, troy operator

When you want to write if... When you use a mitso operator instead of an else statement.

const x = 20; l et answer; if (x > 10) {

Shorthand:

const answer = x > 10 ? 'is greater' : 'is lesser';

Of course, if statements can also be nested:

const big = x > 10 ? " greater 10" : x

4, short-circuit evaluation of shorthand

When assigning another value to a variable, if we want to determine that the source start value is not null, undefined, or empty, we can use the short-circuit evaluation method:

const variable2 = variable1 || 'new';

You can write an if statement that is composed with multiple criteria.

 A must-have for programmers, the ten most commonly used code shorthand techniques in JavaScript3

5, if the existence of conditional shorthand method

if (likeJavaScript === true)

Shorthand:

if (likeJavaScript)

The statements are equal only if the like JavaScript is true

If the judgment value is not true, you can do this:

let a; if ( a !== true ) {// do something...}

Shorthand:

let a; if ( !a ) {// do something...}

6, implicitly return value shorthand

Return statements are often used to return the final result of a function, and an arrow function with a separate statement implicitly returns its value (the function must be omitted).

In order to omit the return keyword) to return a multi-line statement, such as an object literal expression, you need to surround the function body with ().

 A must-have for programmers, the ten most commonly used code shorthand techniques in JavaScript4

Shorthand:

 A must-have for programmers, the ten most commonly used code shorthand techniques in JavaScript5

7, JavaScript loop shorthand method

for (let i = 0; i < allImgs.length; i++)

Shorthand:

for (let index in allImgs)

You can also use Array.forEach:

 A must-have for programmers, the ten most commonly used code shorthand techniques in JavaScript6

8, short-circuit evaluation

A variable is assigned a value by determining whether its value is null or underfined, you can:

let dbHost; if (process.env.DB_HOST) {

Shorthand:

const dbHost = process.env.DB_HOST || 'localhost';

9, decimal index

When you need to write a number band with a lot of zeros (e.g. 10000000), you can replace that number with an index (1e7):

for (let i = 0; i < 10000; i++) {}

Shorthand:

 A must-have for programmers, the ten most commonly used code shorthand techniques in JavaScript7

10, the arrow function shorthand

Traditional function writing methods are easy to understand and write, but if nested in another function, these advantages disappear.

function sayHello(name) { console.log('Hello', name);

Shorthand:

sayHello = name => console.log('Hello', name);