locutus/clojure/core/reduce_kv.js

Locutus other languages' standard libraries to JavaScript for fun and educational purposes

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.reduce_kv = reduce_kv;
function reduce_kv(reducer, initial, collection) {
    //      discuss at: https://locutus.io/clojure/reduce_kv/
    // parity verified: Clojure 1.12
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Reduces map/array entries with key + value, similar to Clojure reduce-kv.
    //       example 1: reduce_kv((acc, key, value) => acc + key + value, '', {a: 1, b: 2})
    //       returns 1: 'a1b2'
    //       example 2: reduce_kv((acc, key, value) => acc + Number(key) * Number(value), 0, [10, 20, 30])
    //       returns 2: 80
    //       example 3: reduce_kv((acc, key, value) => ({...acc, [key]: Number(value) + 1}), {}, {x: 4})
    //       returns 3: {x: 5}
    if (typeof reducer !== 'function') {
        throw new TypeError('reduce_kv(): reducer must be a function');
    }
    let acc = initial;
    if (Array.isArray(collection)) {
        for (let i = 0; i < collection.length; i++) {
            acc = reducer(acc, i, collection[i]);
        }
        return acc;
    }
    if (!collection || typeof collection !== 'object') {
        return acc;
    }
    for (const [key, value] of Object.entries(collection)) {
        acc = reducer(acc, key, value);
    }
    return acc;
}