Increment decrement operator in JavaScript

In JavaScript, incrementing decrements belong to the unary operator, the so-called unary operator, which is an operator that can manipulate only one value.

Increment and decrement operators are available in two versions: pre-and post-built. As the name implies, the predecessor should precede the variable to be manipulated, and the latter should precede the variable to be manipulated.

01, pre-type operator use:

var age=29; //Equals  - equivalent to var age=29;age//equals 

When you perform a pre-increment and decrement operation, the value of the variable is changed before the statement is evaluated.

var num1=2; var num2=20; var num3=--num1+num2;  // equal to var // equal to

02, post-type operator use:

var age=29;age//equals 

There is a very important difference between post increment, decrement and forward increment and decrement, that is, increment and decrement operations are performed after the statement that contains them is evaluated.

var num1=2; var num2=20; var num3=num1--+num2;  // equals var // equal to

All of these four operators apply to any value, that is, they apply not only to integers, but also to strings, Boolean values, floating-point values, and objects.

varS1= "2";varS2= "Z";varb=false;varf=1.1;varo={valueOf:function(){        return-1; }};S1++;//The value becomes the number 3s2++;//value becomes Nanb++;//The value becomes the number 1f--;//value becomes 0.10000000000000009 (due to floating-point rounding errors)o--;//value becomes numeric-2

Increment decrement operator in JavaScript