@toolsycc/json-merge/dist/index.js

A utility to deeply and safely merge JSON objects, with full TypeScript support.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.deepMerge = deepMerge;
exports.mergeMany = mergeMany;
function deepMerge(target, source, options = {}) {
    const { arrayStrategy = 'replace', depthLimit = Infinity, ignoreKeys = [], preserveUndefined = false, customMerge, dateStrategy = 'copy', overwriteFalsy = true, cloneInputs = true } = options;
    if (depthLimit === 0)
        return source;
    const result = cloneInputs ? { ...target } : target;
    for (const key in source) {
        if (ignoreKeys.includes(key))
            continue;
        const val1 = result[key];
        const val2 = source[key];
        if (customMerge) {
            result[key] = customMerge(key, val1, val2);
            continue;
        }
        if (val2 instanceof Date) {
            switch (dateStrategy) {
                case 'stringify':
                    result[key] = val2.toISOString();
                    break;
                case 'timestamp':
                    result[key] = val2.getTime();
                    break;
                default:
                    result[key] = new Date(val2.getTime());
            }
            continue;
        }
        if (val2 &&
            typeof val2 === 'object' &&
            !Array.isArray(val2) &&
            !(val2 instanceof Date)) {
            result[key] = deepMerge(val1 || {}, val2, {
                arrayStrategy,
                depthLimit: depthLimit - 1,
                ignoreKeys,
                preserveUndefined,
                customMerge,
                dateStrategy,
                overwriteFalsy,
                cloneInputs
            });
        }
        else if (Array.isArray(val2)) {
            if (arrayStrategy === 'concat' && Array.isArray(val1)) {
                result[key] = [...val1, ...val2];
            }
            else {
                result[key] = val2;
            }
        }
        else {
            if (val2 === undefined && !preserveUndefined)
                continue;
            if (!overwriteFalsy && val2 == null)
                continue;
            result[key] = val2;
        }
    }
    return result;
}
function mergeMany(objects, options) {
    return objects.reduce((acc, obj) => deepMerge(acc, obj, options), {});
}