CODEWITHSUNDEEP
javascript
totten
totten

Reputation: 2817

What is the + operator before a variable in Javascript?

I was looking into Raphael JS library but I see this:

Animation.prototype.delay = function (delay) {
    var a = new Animation(this.anim, this.ms);
    a.times = this.times;
    a.del = +delay || 0;
    return a;
};

What is the + operator before the delay variable?

Thanks.

Upvotes: 11

Views: 5916

Answers (3)

Rahul Mishra
Rahul Mishra

Reputation: 1

It is a Unary Operator. It converts/parses numbers from a string, boolean or even null values.

It can:

Parse a number from a string, so +"23" returns 23
Parse +True/+False to 1 or 0 respectively.
even +null would return 0.

You can, of course, perform Math.* functions on these above-mentioned returns.

eg. 

let str = "25.5";
Math.ceil(+str) // would return 26

I hope this helps!

Upvotes: 0

KooiInc
KooiInc

Reputation: 122906

It converts a String variable to a Number, if possible: +'21.2' equals Number(21.2). If the conversion fails, it return NaN (that's where || 0 kicks in in your example code)

Upvotes: 18

Yograj Gupta
Yograj Gupta

Reputation: 9869

It is a way to make a variable value to number, if the variable has a number. alternative you can use Number function.

Upvotes: 7

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