Is there any difference in using the " + " operator to push?

Question

I was comparing two branches and there is a divergence in code while the + operator, in my opinion it doesn't make any difference since it's push.
Is there any difference?

Before

if (numberPattern.test(val)) {
            var getNumbers = val.match(numberPattern);
            for (i = 0; i < getNumbers.length; i++) {
                valores.push(getNumbers[i])
            }
        }

After

if (numberPattern.test(val)) {
            var getNumbers = val.match(numberPattern);
            for (i = 0; i < getNumbers.length; i++) {
                valores.push(+getNumbers[i])
            }
        }

The question is what is the use of this operator? I thought unnecessary — Daniela Morais, May 25 '15 at 12:58
possible duplicate of [What is unary + used for in Javascript?](http://stackoverflow.com/questions/9081880/what-is-unary-used-for-in-javascript) — Hacketo, May 25 '15 at 13:03
What i meant to say is that i don't see any difference. Instead if there had been two '+' could have been a problem.. — SharpEdge, May 25 '15 at 13:03
http://stackoverflow.com/questions/15129137/what-does-mean-in-javascript — epascarello, May 25 '15 at 13:09

score 7 · Accepted Answer · answered May 25 '15 at 13:01

7

It is converting it to a Number, where the other case is leaving it as as string.

answered May 25 '15 at 13:01

Daniel A. White

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how do you know that `getNumber[i]` is returning a string? – Amit Joki May 25 '15 at 13:04
1

Note that this technique differs from `parseFloat` in that it will convert booleans and empty strings as well ( + other edge cases ) I would not recommend it however because of readability. – Willem D'Haeseleer May 25 '15 at 13:07
1

@AmitJoki its because of the regex processing. – Daniel A. White May 25 '15 at 13:07
Ah! yes. Didn't look at it. Thanks for the clarification though. – Amit Joki May 25 '15 at 13:10

score 2 · Answer 2 · answered May 25 '15 at 13:01

+ will actually change getNumbers[i] to a number type. The +(unary operator) is actually used to convert it to a number.

Try running this code:

var s = "1"; //String
var s1 = +s; //String changed to a number now
console.log(typeof s1);

You will see the type of s1 will be number.

Is there any difference in using the " + " operator to push?

2 Answers2