Clarification of array example

[PierBover]

It was a bit confusing that the value added was the length of the array. I added a value var to make the example more obvious to all audiences.

[codecov-io]

Codecov Report

Merging #2491 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2491   +/-   ##
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  Coverage   91.83%   91.83%           
=======================================
  Files           1        1           
  Lines          49       49           
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  Hits           45       45           
  Misses          4        4

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[Rich-Harris]

Thanks, but this wouldn't actually work, because you're not passing a value to addNumber — you're passing an event object instead:

1 + 2 + 3 + 4 + [object MouseEvent] + [object MouseEvent] = 10[object MouseEvent][object MouseEvent]

The way to fix that would be to put the same logic inline...

-<button on:click={addNumber}>
+<button on:click={() => addNumber(numbers.length + 1)}>
  Add a number
</button> 

...which puts us back where we started. The only alternative would be to keep track of n separately, like this...

let n = 1;
let numbers = [n++, n++, n++, n++];

function addNumber() {
  numbers = [...numbers, n++];
}

...but that doesn't seem clearer to me. I don't think it's a stretch to expect folks to understand what numbers.length is.