CODEWITHSUNDEEP
javascript
henriettalLUx
henriettalLUx

Reputation: 81

JS: alternative to using filtering and mapping together?

I am trying to return an array of the names who are not enabled.

let arr = [
   { enabled: false, name: 'Cal'},
   { enabled: true, name: 'John'},
   { enabled: false, name: 'Phil'},
   { enabled: true, name: 'Pierre'}
]

I am doing so with:

 arr.filter(x => x.enabled).map(y => y.name)

Is there a cleaner way of doing this?

Upvotes: 1

Views: 1199

Answers (3)

razorcat
razorcat

Reputation: 73

I ran some performance tests on some alternatives I've thought of. They assume the filter removes about 50% of the elements. https://jsbench.me/xll0cli8cm/1

A simple for-of loop is by far the fastest, and in my opinion more readable than reduce is.

Perf test results

Upvotes: 1

Vasudev Bhat
Vasudev Bhat

Reputation: 229

U can use reduce() function too.

let arr = [
  {enabled:false,name:'Cal'},
  {enabled:true,name:'John'},
  {enabled:false,name:'Phil'},
  {enabled:true,name:'Pierre'}
];

var filteredArray = arr.reduce((a,b)=> {
  if (b.enabled) {
  a.push(b.name);
  }
  return a;
},[]);
console.log(filteredArray)

Upvotes: 0

Craques
Craques

Reputation: 1133

You can use flatMap here is the documentation

let arr = [
    { enabled: false, name: 'Cal'},
    { enabled: true, name: 'John'},
    { enabled: false, name: 'Phil'},
    { enabled: true, name: 'Pierre'}
]

//empty brackets return null
const mappedArr = arr.flatMap((item)=>{
    return item.enabled ? [item.name] : []
})
 console.log(mappedArr)

Upvotes: 0

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