Array forEach() vs reduce()

Question

what do you think is the best way to do ?

Reduce Way :

const result = Object.keys(params).reduce(
      (previous, key) => {
        if (this.model.hasOwnProperty(key)) previous[key] = this.model[key](params[key]);
        return previous;
  }, {});

ForEach Way:

const result = {};
Object.keys(params).forEach(key => {
      if (this.model.hasOwnProperty(key)) result[key] = this.model[key](params[key]);
    });

I'm using airbnb eslint and it doesn't like the reduce way since I modify previous (no-param-reassign)

if you don't need to "roll up" an array values - use `forEach` function — RomanPerekhrest, May 26 '16 at 13:38
Since you are asking about ES6, `.forEach` is effectively deprecated by `for … of`. — Bergi, May 26 '16 at 13:52
Maybe but since I follow airbnb : https://github.com/airbnb/javascript#iterators-and-generators — Titozzz, May 26 '16 at 13:57

score 2 · Accepted Answer · answered May 26 '16 at 13:14

2

I think the reduce is a lot nicer because it doesn't spill vars all over the place. You could make it a little better yet, imo.

var result = Object.keys(params).reduce((res,k)=>
  this.model.hasOwnProperty(k)
    ? Object.assign(res, {[k]: this.model[k](params[k])})
    : res, {});

answered May 26 '16 at 13:14

Mulan

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Ah, `Object.assign` seems to be an effective way of working around the linter :-) – Bergi May 26 '16 at 13:52
Use spread operator instead of object.assign – Sonu Kapoor Jul 07 '17 at 20:53
@skone you can use object spread *syntax* if you want, but since it's not supported in most environments, I don't recommend it unless your project already has a transpile step – Mulan Jul 07 '17 at 20:55
makes sense. .... – Sonu Kapoor Jul 07 '17 at 20:57

Array forEach() vs reduce()

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