refactor: array loop to Array.forEach

[curbengh]

No description provided.

[coveralls]

Coverage remained the same at 100.0% when pulling b58a674 on array-map into 64f8583 on master.

[curbengh]

initially, I wanted to

const result = languages.map(...)

but I don't know exactly how to return object { [key]: data[lang][key] }.

[segayuu]

The following is my own opinion.
Array.prototype.forEach() looks beautiful because it eliminates some of the temporary variables, but I do not think that it will have a very good effect except for it.
When trying to break a loop, Array#forEach() has no way to do it (except to throw an exception) and needs to rewrite the whole loop.
Also, compared with Array#map() and Array#filter(), it does not make clearer intention than for loop.
If I conclude that I like it, I can not merge this PR.

[segayuu]

I know that we can assign from an array to an object by using Array#reduce().
I like Array#reduce(), but like Array#forEach(), can write approximate content, so some people may not like it.

[curbengh]

I see. forEach() cannot do if (!langData) continue;. What about the refactor in line 63? It doesn't seem have a need to break a loop.

btw, the first case doesn't need to break a loop, only skip it, so I can add a check,

  languages.forEach(lang => {
    Object.keys(data[lang]).forEach(key => {
      if (data[lang] && !Object.prototype.hasOwnProperty.call(result, key)) {
        result[key] = data[lang][key];
      }
    });

wouldn't if (data[lang]) {} have the same effect as if (!langData) continue;?

[segayuu]

@curbengh Your opinion is correct.
In fact, the reason for not merging this PR is just my religious and coding guide.
I personally will not merge this PR, but I think that it may be merged upon review by other people :)

[tcrowe]

👍

[curbengh]

added another check.