CFP - Docs - flattenToDepth

flattenToDepth

(depth: number) => (anArray: array) => array

Flatten an array N levels deep.

Try It

const flattenTwice = flattenToDepth(2)
flattenTwice(['a', ['b', ['c', ['d']]]]) // is ['a', 'b', 'c', ['d']]
const flattenTwice = flattenToDepth(2)
flattenTwice(['a', ['b', ['c', ['d']]]]) // is ['a', 'b', 'c', ['d']]

Try It

const flattenTwice = flattenToDepth(2)
flattenTwice(['a', ['b', ['c', ['d']]]]) // is ['a', 'b', 'c', ['d']]
const flattenTwice = flattenToDepth(2)
flattenTwice(['a', ['b', ['c', ['d']]]]) // is ['a', 'b', 'c', ['d']]

Sometimes we have nested arrays and only want to flatten to a specific depth. Below, Grace's corporation voted to give out bonuses due to their success. Only the highest-ranking employees deserve them, so let's find our top three tiers from our corporate tree.

Try It

const managers = ['meg', 'tom', 'ken']
const vicePresidents = ['mike', 'luke', 'emma']
const cSuite = ['sam', 'jen']
const ceo = 'grace'

const corporateTiers = [ceo, [...cSuite, [...vicePresidents, [...managers]]]]

const isString = element => typeof element === 'string'
const flattenToVPs = flattenToDepth(2)
const employeesWhoGetBonuses = flattenToVPs(corporateTiers).filter(isString)
console.log(employeesWhoGetBonuses)
// is [
//   grace,
//   sam,
//   jen,
//   mike,
//   luke,
//   emma,
// ]
const managers = ['meg', 'tom', 'ken']
const vicePresidents = ['mike', 'luke', 'emma']
const cSuite = ['sam', 'jen']
const ceo = 'grace'

type CorporateTiers = (string | CorporateTiers)[]
const corporateTiers: CorporateTiers = [
  ceo,
  [...cSuite, [...vicePresidents, [...managers]]],
]

const isString = (node: string | CorporateTiers) => typeof node === 'string'
const flattenToVPs = flattenToDepth(2)
const employeesWhoGetBonuses = flattenToVPs(corporateTiers).filter(isString)
console.log(employeesWhoGetBonuses)
// is [
//   grace,
//   sam,
//   jen,
//   mike,
//   luke,
//   emma,
// ]

Try It

const managers = ['meg', 'tom', 'ken']
const vicePresidents = ['mike', 'luke', 'emma']
const cSuite = ['sam', 'jen']
const ceo = 'grace'

const corporateTiers = [
  ceo,
  [...cSuite, [...vicePresidents, [...managers]]],
]

const isString = element =>
  typeof element === 'string'
const flattenToVPs = flattenToDepth(2)
const employeesWhoGetBonuses = flattenToVPs(
  corporateTiers
).filter(isString)
console.log(employeesWhoGetBonuses)
// is [
//   grace,
//   sam,
//   jen,
//   mike,
//   luke,
//   emma,
// ]
const managers = ['meg', 'tom', 'ken']
const vicePresidents = ['mike', 'luke', 'emma']
const cSuite = ['sam', 'jen']
const ceo = 'grace'

type CorporateTiers = (string | CorporateTiers)[]
const corporateTiers: CorporateTiers = [
  ceo,
  [...cSuite, [...vicePresidents, [...managers]]],
]

const isString = (
  node: string | CorporateTiers
) => typeof node === 'string'
const flattenToVPs = flattenToDepth(2)
const employeesWhoGetBonuses = flattenToVPs(
  corporateTiers
).filter(isString)
console.log(employeesWhoGetBonuses)
// is [
//   grace,
//   sam,
//   jen,
//   mike,
//   luke,
//   emma,
// ]