What does the "=>" symbol do in JavaScript?

Asked Sep 28 '15 at 13:24

Active Sep 28 '15 at 13:27

Viewed 56 times

I was looking at a solution on Codewars and I'm confused by the "=>" symbol. I thought the filter method had to take a callback function and although I can see the logic behind what's happening, I have not seen the symbol used before and can't find any reference to it on the internet.

function move_zeros(arrNum, isRight = true) {
  let zeroes    = arrNum.filter(i => i === 0);
  let nonZeroes = arrNum.filter(i => i !== 0);

  return isRight ?
    nonZeroes.concat(zeroes) :
    zeroes.concat(nonZeroes);
}

asked Sep 28 '15 at 13:24

Ivan Gonzalez

1

Look up "fat arrow JavaScript" – John Dvorak Sep 28 '15 at 13:26
2

See [*MDN Arrow Functions*](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions). Note that *this* is set to the same value as the containing execution context. – RobG Sep 28 '15 at 13:26
@JanDvorak: JavaScript has arrow functions, but not "fat arrows". – Felix Kling Sep 28 '15 at 13:33
@FelixKling Google "fat arrow Javascript" and you might change your mind :) – Steve Bennett Sep 28 '15 at 13:48
1

@SteveBennett: that doesn't mean we have to make the same mistake. The official term is "arrow function" and I'd say we just stick with that :) – Felix Kling Sep 28 '15 at 13:59
@felix but, would you accept "fat arrow" as a general name for the symbol irrespective of the language it is in? – John Dvorak Sep 28 '15 at 14:00

What does the "=>" symbol do in JavaScript?

0 Answers0