locutus/esm/clojure/core/get_in.js

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

function readAtPath(target, key) {
    if (target === null || target === undefined) {
        return undefined;
    }
    if (typeof target !== 'object') {
        return undefined;
    }
    return target[key];
}
export function get_in(value, keys, defaultValue) {
    //      discuss at: https://locutus.io/clojure/get_in/
    // parity verified: Clojure 1.12
    //     original by: Kevin van Zonneveld (https://kvz.io)
    //          note 1: Reads nested values by path, similar to Clojure get-in.
    //       example 1: get_in({a: {b: 42}}, ['a', 'b'])
    //       returns 1: 42
    //       example 2: get_in({a: {b: 42}}, ['a', 'c'], 'fallback')
    //       returns 2: 'fallback'
    //       example 3: get_in([10, {x: [1, 2, 3]}], [1, 'x', 2], null)
    //       returns 3: 3
    if (!Array.isArray(keys)) {
        return defaultValue;
    }
    if (keys.length === 0) {
        return value;
    }
    let cursor = value;
    for (const key of keys) {
        cursor = readAtPath(cursor, key);
        if (cursor === undefined) {
            return defaultValue;
        }
    }
    return cursor;
}