What does the + mean in +a[i]

Question

I'm trying to figure out how some javascript code for creating pagination is working and I ran across this line:

if (+a[i].innerHTML === Pagination.page) a[i].className = 'current';

I was just wondering what the + is doing in this +a[i]. Here is the rest of that section of code just in case.

Bind: function() {
    var a = Pagination.e.getElementsByTagName('a');
    for (var i = 0; i < a.length; i++) {
        if (+a[i].innerHTML === Pagination.page) a[i].className = 'current';
        a[i].addEventListener('click', Pagination.Click, false);
    }
},

implicit conversion to `number`, it's like saying `0 + a[i].innerHTML` (but not exactly `+"abc" === NaN` `0+"abc" === "0abc"`) — Patrick Barr, Jul 11 '17 at 14:33

score 1 · Answer 1 · answered Jul 11 '17 at 14:33

1

It converts it to a number.

+"234" => 234

answered Jul 11 '17 at 14:33

c2huc2hu

2,447
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score 0 · Accepted Answer · answered Jul 11 '17 at 14:35

0

It's the unary plus operator:

The unary plus operator precedes its operand and evaluates to its operand but attempts to convert it into a number, if it isn't already

For example

+"15" === 15

answered Jul 11 '17 at 14:35

Johan Karlsson

6,419
1
19
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What does the + mean in +a[i]

2 Answers2