fatten/lib/index.js

restructures flat objects with dot-notation-like keys into optimised nested objects

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.fatten = void 0;
function camelJoin(first, second) {
    return first + second.charAt(0).toUpperCase() + second.slice(1);
}
function blowUpWith(options) {
    function blowUp(acc, [key, condition]) {
        const [context, ...rest] = key.split(options.separator);
        if (!rest.length) {
            return {
                ...acc,
                [context]: {
                    ...(acc[context] ?? {}),
                    [options.leafKey]: condition,
                },
            };
        }
        return {
            ...acc,
            [context]: blowUp(acc[context] ?? {}, [rest.join(options.separator), condition]),
        };
    }
    return blowUp;
}
function deflate(nested, leafKey) {
    return Object.fromEntries(Object.entries(nested).map(([key, value]) => {
        if (key === leafKey)
            return [key, value];
        const values = Object.entries(value);
        if (values.length === 1) {
            const [nodeKey, nodeValue] = values[0];
            if (nodeKey === leafKey) {
                return [key, nodeValue];
            }
            else {
                return Object.entries(deflate({ [camelJoin(key, nodeKey)]: nodeValue }, leafKey))[0];
            }
        }
        return [key, deflate(value, leafKey)];
    }));
}
function fatten(object, { separator = '.', leafKey = '_' } = { separator: '.', leafKey: '_' }) {
    return deflate(Object.entries(object).reduce(blowUpWith({ separator, leafKey }), {}), leafKey);
}
exports.fatten = fatten;