Basic specifications of JavaScript

As everyone knows, each programming language has its own coding standards. The following are the basic coding standards for JavaScript that I have compiled.

1. Do not declare multiple variables on the same line

var a = null;var b = 0;var c = undefined;123

2. Please use ===/!== to compare true/false or numerical values ​​

var a = 1;var b = '2';
if(a === b){ console.log(a);
}else{ console.log(b);
}

3. Use literals instead of new Array() This form

var arr = [];

4. Do not use global functions

5.Switch must Use the default branch

switch（num）{
case 1:
    num++;
    breake;
case 2:
    num--;
    breake;
case 3:
    num = 0;
    breake;
default:
    num = 1;
}

6. Functions should not sometimes have a return value and sometimes not (it is recommended to have a return value: undefined)

7. For loops and if statements must use curly braces

for（var i=0 ；i<10; i++）{
    console.log(i);
}

##8. The variables in the for in loop should use the var keyword to limit the scope, so as to avoid scope pollution

for(var i in obj){
console.log(obj);
}

Related articles:
JavaScript Date (date) related knowledge and usage

Introduction to the use of JavaScript RegExp objects

About how to use JavaScript Array (array) object

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