refactor code that filters based on value of key/value pairs

Question

I have the following code, which works as expected - it properly filters out key/value pairs with value of null, false and returns an object with the other key/value pairs. However, it's rather verbose and I'm wondering if there's a way to simplify it.

 const settings = { distance: null, length: 23, weight: null, isActive: false, isRound: true } const data = {}; Object.entries(settings) .filter(([, value]) => value !== null) .filter(([, value]) => value !== false) .forEach(([key, value]) => (data[key] = value)); console.log(data);

Answer 1

You can remove all falsy values and iterate just once:

 const settings = { distance: null, length: 23, weight: null, isActive: false, isRound: true } const data = {}; Object.entries(settings) .forEach(([key, value]) => { if(!!value) { data[key]= value; } }) console.log(data);

Answer 2

What about using a reducer instead of your forEach ?

 const settings = { distance: null, length: 23, weight: null, isActive: false, isRound: true } const data = Object.entries(settings) .filter(([, value]) => value !== null && value !== false) .reduce((acc, [key, value]) => { (acc[key] = value); return acc; }, {}); console.log(data);

Answer 3

In vanilla javscript it would be more easier in a single loop

const settings = {
    distance: null,
    length: 23,
    weight: null,
    isActive: false,
    isRound: true
}

const data = {}

for(var key in settings) {
    if(settings[key] !== false && settings[key] !== null) {
        data[key] = settings[key];
    }
}

Not sure why to use multiple filter methods and reduce as it will cause additional iterations.

Answer 4

As an alternative, here's a bit of an arguably simpler, but not functional version that uses mutability to delete the offending keys:

 const settings = { distance: null, length: 23, weight: null, isActive: false, isRound: true } const copy = Object.assign({}, settings); Object.entries(copy).forEach(([key, value]) => { if (value === null || value === false) delete copy[key]; }); console.log(copy);

A bit shorter, if it's to your taste.

Answer 5

why don't you check these condition in one iteration

change this

.filter(([, value]) => value !== null)
.filter(([, value]) => value !== false)

to

.filter(([, value]) => !!value)

or make use of single loop which checks condition and append data in data object eg:

Object.entries(settings)
      .forEach(([key, value]) => {
        if(!!value) {
          data[key]= value;       
        }
     })