isArrayDuplicated.js

isArrayDuplicated.js

function isArrayDuplicated (array, ...getters) {
  if (!Array.isArray(array) || getters.some(getter => typeof getter !== 'function')) {
    return
  }
  const preGetters = [...getters]
  const lastGetter = preGetters.pop()
  const result = array.reduce((temp, wantedItem) => {
    if (temp === true || temp === undefined) return temp
    const slot = preGetters.reduce((t, getter) => {
      if (t === undefined) return
      if (!['number', 'string'].includes(typeof getter(wantedItem))) return
      if (t[getter(wantedItem)] === undefined) t[getter(wantedItem)] = []
      return t[getter(wantedItem)]
    }, temp)
    if (slot === undefined) return
    if (slot[lastGetter(wantedItem)] !== undefined) return true
    slot[lastGetter(wantedItem)] = true
    return temp
  }, [])
  return (result === true || result === undefined) ? result : false
}

const result = isArrayDuplicated(
  [
    { a: 3, b: 2, c: {d: 4}, e: 'do', f: 'not', g: 'care' },
    { a: 2, b: 2, c: {d: 4}, e: 'do', f: 'not', g: 'care' },
    { a: 3, b: 2, c: {d: 3}, e: 'do', f: 'not', g: 'care' },
    { a: 2, b: 4, c: {d: 4}, e: 'do', f: 'not', g: 'care' }
  ],
  o => o.a,
  o => o.b,
  o => o.c.d
)

console.log(result)