rambda/src/groupBy.js

Lightweight and faster alternative to Ramda with included TS definitions

export function groupByFallback(groupFn, list) {
    const result = {}
    for (let i = 0; i < list.length; i++) {
      const item = list[i]
      const key = groupFn(item)

      if (!result[key]) {
        result[key] = []
      }

      result[key].push(item)
    }

    return result
}


export function groupBy(groupFn) {
  return iterable => Object.groupBy ? Object.groupBy(iterable,groupFn) : groupByFallback(groupFn, iterable)
}