[JavaScript Practice]--"Kinky tricks" you don't know.

1. Null (null, undefined) validation

At first, I was a bit of a fool to verify (I really did)

if (variable1!== null | | variable1!== undefined | | variable1!== ") {Let variable2 = variable1;}

Big Brother taught me this, you'll marvel.

Let Variable2 = variable1  | | ‘‘;

If you don't believe it, try it under the console of the Google Chrome developer Dashboard!

Example of a null value let Variable1 = Null;let variable2 = variable1  | | "; Console.log (variable2);//output:"//value is undefined example let variable1 = Undefined;let variable2 = variable1  | | '; Console.log (variable2);//output: '//normal let variable1 = ' Hi there '; let Variable2 = Variable1  | | "; Console.log (variable2);//output: ' Hi there '

Isn't it great (cute face)

2. Arrays

This is often used, like I do not have a problem

Let a = ["MyString1", "MyString2", "MyString3"];

3. If true: Else's optimization

is actually using ternary arithmetic

Let big;if (x > Ten) {    big = true;} else {    big = false;}

It can turn out like this.

Let big = x > 10? True:false;

is not concise, ternary operations can be used in many places, (Vue inside to determine the loading of components,, is not irrelevant)

One more example.

< 5    = x > Ten, false:x < =10}; Console.log (big); "Object {truefalse=false}"

4. Variable declaration

Variable declarations, such as the Let X of the child; Let y;

It's as simple and clear as I am.

Let x, Y, z=3;

5. Simplification of assignment statements

At first, it was like this.

X=x+1;minuscount = minuscount-1;y=y*10;

Turned into

X++;minuscount--;y*=10;

6. Avoid using RegExpObject

Regular expressions, do you want to use the

var re = new RegExp ("\d+ (.)" +\d+ "," IgM "), result = Re.exec (" padding 01234 text text 56789 padding "); Console.log (result); "01234 text text 56789"

Simplify

var result =/d+ (.) +d+/igm.exec ("padding 01234 text text 56789 padding"); Console.log (result); "01234 text text 56789"

7. If Condition Optimization

Although it is very simple, it is worth mentioning.

if (likejavascript)

Is it better to be better than the word?

if (Likejavascript = = = True)

8. Function calls can also be shorter

function X () {Console.log (' x ')};function y () {console.log (' y ')};let z = 3;if (z = = 3) {    x ();} else {    y ();}

Actually, it's the function self-tuning.

function X () {Console.log (' x ')};function y () {console.log (' y ')};let z = 3; (z==3?x:y) ();

9. How to gracefully represent a large number

In JavaScript, there's a shorthand for a number, and maybe you're ignoring it. 1e7represents 10000000.

Before simplifying:

< 10000 ; i++) {

Le7 ..... ..... ..... ........................... ..... ..... ..... ..... .............. ........... (Naughty AH)

< 1e7 ; i++) {

What do you mean, four-odd kinky tricks?

Respect for our original author Ka

Copyright NOTICE: Please specify the author Fundebug and this address: https://blog.fundebug.com/2017/07/06/12-tricks-that-js-rocks/

[JavaScript Practice]--"Kinky tricks" you don't know.