CFP - Docs - compareByProp

compareByProp

(key: PropertyKey, compareFn: CompareFn) => CompareFn

Create a function comparing properties intended for built-in methods such as toSorted.

Below, we sort an array of people by name.

Try It

const people = [{ name: 'mike' }, { name: 'emma' }, { name: 'luke' }]
const ascending = (left, right) => left.localeCompare(right)
const byName = compareByProp('name', ascending)

const sortedPeople = people.toSorted(byName)
console.log(sortedPeople)
// is [
//  { name: 'emma' },
//  { name: 'luke' },
//  { name: 'mike' },
// ]
const people = [{ name: 'mike' }, { name: 'emma' }, { name: 'luke' }]
const ascending = (left: string, right: string) => left.localeCompare(right)
const byName = compareByProp('name', ascending)

const sortedPeople = people.toSorted(byName)
console.log(sortedPeople)
// is [
//  { name: 'emma' },
//  { name: 'luke' },
//  { name: 'mike' },
// ]

Try It

const people = [
  { name: 'mike' },
  { name: 'emma' },
  { name: 'luke' },
]
const ascending = (left, right) =>
  left.localeCompare(right)
const byName = compareByProp('name', ascending)

const sortedPeople = people.toSorted(byName)
console.log(sortedPeople)
// is [
//  { name: 'emma' },
//  { name: 'luke' },
//  { name: 'mike' },
// ]
const people = [
  { name: 'mike' },
  { name: 'emma' },
  { name: 'luke' },
]
const ascending = (left: string, right: string) =>
  left.localeCompare(right)
const byName = compareByProp('name', ascending)

const sortedPeople = people.toSorted(byName)
console.log(sortedPeople)
// is [
//  { name: 'emma' },
//  { name: 'luke' },
//  { name: 'mike' },
// ]

We often want to sort data by a property. The example in 'What' shows this.
Undefined properties are handled by compareByProp as defined in the spec, so compareFn will not need to handle them.