import type { GroupByOpts , Reducer } from "./api.js" ; import { __groupByOpts } from "./internal/group-opts.js" ; import { $$reduce } from "./reduce.js" ; export function groupByMap < SRC , KEY , GROUP > ( opts ? ) ; export function groupByMap < SRC , GROUP > ( xs ) ; export function groupByMap < SRC , KEY , GROUP > ( opts , xs ) ; export function groupByMap < SRC , KEY , GROUP > ( ... args ) { const res = $$reduce ( groupByMap , args ) ; if ( res !== undefined ) { return res ; } const opts = __groupByOpts < SRC , KEY , GROUP > ( args [ 0 ] ) ; const [ init , complete , reduce ] = opts . group ; return < Reducer < Map < KEY , GROUP > , SRC > > [ ( ) => new Map ( ) , ( acc ) => { for ( let k of acc . keys ( ) ) { acc . set ( k , complete ( acc . get ( k ) ! ) ) ; } return acc ; } , ( acc , x ) => { const k = opts . key ( x ) ; return acc . set ( k , acc . has ( k ) ? < GROUP > reduce ( acc . get ( k ) ! , x ) : < GROUP > reduce ( init ( ) , x ) ) ; } , ] ; }