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Function: toGrouped()

Returns a Reducer that reduces key-value pairs using outerReducer and reduces values with the same key using innerReducer.

Example​

import { map, pipe, reduce, toArray, toGrouped, toMap } from 'lfi'

console.log(
  pipe(
    [`sloth`, `lazy`, `sleep`],
    map(word => [word.length, word]),
    reduce(toGrouped(toArray(), toMap())),
  ),
)
//=> Map(2) {
//=>   5 => [ 'sloth', 'sleep' ],
//=>   4 => [ 'lazy' ]
//=> }
Playground

Since​

v2.0.0

Call Signature​

toGrouped<Key, Value, InnerAcc, InnerFinished, InnerThis, OuterAcc, OuterThis>(innerReducer, outerReducer): Reducer<readonly [Key, Value], never, OuterAcc>

Type Parameters​

• Key

• Value

• InnerAcc

• InnerFinished

• InnerThis

• OuterAcc

• OuterThis

Parameters​

innerReducer​

Readonly<RawReducerWithFinish<Value, InnerAcc, InnerFinished, InnerThis>>

outerReducer​

Readonly<RawKeyedReducer<Key, InnerAcc | InnerFinished, OuterAcc, OuterThis>>

Returns​

Reducer<readonly [Key, Value], never, OuterAcc>

Defined in​

collections.d.ts:204

Call Signature​

toGrouped<Value, InnerAcc, InnerFinished, InnerThis>(innerReducer): <Key, OuterAcc, OuterThis>(outerReducer) => Reducer<readonly [Key, Value], never, OuterAcc>

Type Parameters​

• Value

• InnerAcc

• InnerFinished

• InnerThis

Parameters​

innerReducer​

Readonly<RawReducerWithFinish<Value, InnerAcc, InnerFinished, InnerThis>>

Returns​

Function

Type Parameters​

• Key

• OuterAcc

• OuterThis

Parameters​

outerReducer​

Readonly<RawKeyedReducer<Key, InnerAcc | InnerFinished, OuterAcc, OuterThis>>

Returns​

Reducer<readonly [Key, Value], never, OuterAcc>

Defined in​

collections.d.ts:212

Call Signature​

toGrouped<Key, Value, InnerAcc, InnerThis, OuterAcc, OuterThis>(innerReducer, outerReducer): Reducer<readonly [Key, Value], never, OuterAcc>

Type Parameters​

• Key

• Value

• InnerAcc

• InnerThis

• OuterAcc

• OuterThis

Parameters​

innerReducer​

Readonly<RawReducerWithoutFinish<Value, InnerAcc, InnerThis>>

outerReducer​

Readonly<RawKeyedReducer<Key, InnerAcc, OuterAcc, OuterThis>>

Returns​

Reducer<readonly [Key, Value], never, OuterAcc>

Defined in​

collections.d.ts:222

Call Signature​

toGrouped<Value, InnerAcc, InnerThis>(innerReducer): <Key, OuterAcc, OuterThis>(outerReducer) => Reducer<readonly [Key, Value], never, OuterAcc>

Type Parameters​

• Value

• InnerAcc

• InnerThis

Parameters​

innerReducer​

Readonly<RawReducerWithoutFinish<Value, InnerAcc, InnerThis>>

Returns​

Function

Type Parameters​

• Key

• OuterAcc

• OuterThis

Parameters​

outerReducer​

Readonly<RawKeyedReducer<Key, InnerAcc, OuterAcc, OuterThis>>

Returns​

Reducer<readonly [Key, Value], never, OuterAcc>

Defined in​

collections.d.ts:226

Call Signature​

toGrouped<Key, Value, InnerFinished, InnerThis, OuterAcc, OuterThis>(innerReducer, outerReducer): Reducer<readonly [Key, Value], never, OuterAcc>

Type Parameters​

• Key

• Value

• InnerFinished

• InnerThis

• OuterAcc

• OuterThis

Parameters​

innerReducer​

Readonly<RawOptionalReducerWithFinish<Value, InnerFinished, InnerThis>>

outerReducer​

Readonly<RawKeyedReducer<Key, Value | InnerFinished, OuterAcc, OuterThis>>

Returns​

Reducer<readonly [Key, Value], never, OuterAcc>

Defined in​

collections.d.ts:232

Call Signature​

toGrouped<Value, InnerFinished, InnerThis>(innerReducer): <Key, OuterAcc, OuterThis>(outerReducer) => Reducer<readonly [Key, Value], never, OuterAcc>

Type Parameters​

• Value

• InnerFinished

• InnerThis

Parameters​

innerReducer​

Readonly<RawOptionalReducerWithFinish<Value, InnerFinished, InnerThis>>

Returns​

Function

Type Parameters​

• Key

• OuterAcc

• OuterThis

Parameters​

outerReducer​

Readonly<RawKeyedReducer<Key, Value | InnerFinished, OuterAcc, OuterThis>>

Returns​

Reducer<readonly [Key, Value], never, OuterAcc>

Defined in​

collections.d.ts:240

Call Signature​

toGrouped<Key, Value, InnerThis, OuterAcc, OuterThis>(innerReducer, outerReducer): Reducer<readonly [Key, Value], never, OuterAcc>

Type Parameters​

• Key

• Value

• InnerThis

• OuterAcc

• OuterThis

Parameters​

innerReducer​

Readonly<RawOptionalReducerWithoutFinish<Value, InnerThis>>

outerReducer​

Readonly<RawKeyedReducer<Key, Value, OuterAcc, OuterThis>>

Returns​

Reducer<readonly [Key, Value], never, OuterAcc>

Defined in​

collections.d.ts:250

Call Signature​

toGrouped<Value, InnerThis>(innerReducer): <Key, OuterAcc, OuterThis>(outerReducer) => Reducer<readonly [Key, Value], never, OuterAcc>

Type Parameters​

• Value

• InnerThis

Parameters​

innerReducer​

Readonly<RawOptionalReducerWithoutFinish<Value, InnerThis>>

Returns​

Function

Type Parameters​

• Key

• OuterAcc

• OuterThis

Parameters​

outerReducer​

Readonly<RawKeyedReducer<Key, Value, OuterAcc, OuterThis>>

Returns​

Reducer<readonly [Key, Value], never, OuterAcc>

Defined in​

collections.d.ts:254

Call Signature​

toGrouped<Key, Value, OuterAcc, OuterThis>(innerReducer, outerReducer): Reducer<readonly [Key, Value], never, OuterAcc>

Type Parameters​

• Key

• Value

• OuterAcc

• OuterThis

Parameters​

innerReducer​

FunctionReducer<Value>

outerReducer​

Readonly<RawKeyedReducer<Key, Value, OuterAcc, OuterThis>>

Returns​

Reducer<readonly [Key, Value], never, OuterAcc>

Defined in​

collections.d.ts:260

Call Signature​

toGrouped<Value>(innerReducer): <Key, OuterAcc, OuterThis>(outerReducer) => Reducer<readonly [Key, Value], never, OuterAcc>

Type Parameters​

• Value

Parameters​

innerReducer​

FunctionReducer<Value>

Returns​

Function

Type Parameters​

• Key

• OuterAcc

• OuterThis

Parameters​

outerReducer​

Readonly<RawKeyedReducer<Key, Value, OuterAcc, OuterThis>>

Returns​

Reducer<readonly [Key, Value], never, OuterAcc>

Defined in​

collections.d.ts:264