@open-kappa/myjson/dist/myjson/mergeJson.js

A simple JSON management library.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.mergeJson = exports.JsonMergePolicy = void 0;
/* eslint-disable no-shadow */
/**
 * @brief Enum to list possible behaviors in case of conflicting values
 * during JSON merge.
 */
var JsonMergePolicy;
(function (JsonMergePolicy) {
    JsonMergePolicy[JsonMergePolicy["KEEP_LEFT"] = 0] = "KEEP_LEFT";
    JsonMergePolicy[JsonMergePolicy["KEEP_RIGHT"] = 1] = "KEEP_RIGHT";
    JsonMergePolicy[JsonMergePolicy["CONFLICT"] = 2] = "CONFLICT";
})(JsonMergePolicy || (JsonMergePolicy = {}));
exports.JsonMergePolicy = JsonMergePolicy;
/* eslint-enable no-shadow */
/**
 * @brief Merge two arrays.
 * @private
 * @param {Array<any>} a1 The left array.
 * @param {Array<any>} a2 The right array.
 * @param {JsonMergePolicy} policy The merge policy.
 * @param {(j1: any, j2: any) => boolean} arrayComparator The element
 *     comparator.
 * @return {Error | null} null in case of success.
 */
function _mergeTwoArrays(a1, a2, policy, arrayComparator) {
    for (let i = 0; i < a2.length; ++i) {
        const e2 = a2[i];
        let found = false;
        let j = 0;
        for (; j < a1.length; ++j) {
            const e1 = a1[j];
            found = arrayComparator(e1, e2);
            if (found)
                break;
        }
        if (!found) {
            a1.push(e2);
        }
        else {
            const e1 = a1[j];
            // eslint-disable-next-line no-use-before-define
            const ret = _mergeObjectHelper(a1, j, e1, e2, policy, arrayComparator);
            if (ret !== null)
                return ret;
        }
    }
    return null;
}
/**
 * @brief Merge two objects.
 * @private
 * @param {any} o1 The left parent object.
 * @param {string | number} k The key under merging.
 * @param {any} v1 The left value.
 * @param {any} v2 The right value.
 * @param {JsonMergePolicy} policy The merge policy.
 * @param {(j1: any, j2: any) => boolean} arrayComparator The element
 *     comparator.
 * @return {Error | null} null in case of success.
 */
function _mergeObjectHelper(o1, k, v1, v2, policy, arrayComparator) {
    const t1 = typeof v1;
    const t2 = typeof v2;
    if (Array.isArray(v1) && Array.isArray(v2)) {
        return _mergeTwoArrays(v1, v2, policy, arrayComparator);
    }
    else if (t1 !== t2) {
        // Keep one:
        switch (policy) {
            case JsonMergePolicy.KEEP_LEFT:
                return null;
            case JsonMergePolicy.KEEP_RIGHT:
                o1[k] = v2;
                return null;
            case JsonMergePolicy.CONFLICT:
                return new Error("Conflict on key " + k);
            default:
        }
    }
    else if (t1 === "object") {
        // eslint-disable-next-line no-use-before-define
        return _mergeTwoObjects(v1, v2, policy, arrayComparator);
    }
    else if (t1 === "number"
        || t1 === "string"
        || t1 === "boolean") {
        // Keep one:
        switch (policy) {
            case JsonMergePolicy.KEEP_LEFT:
                return null;
            case JsonMergePolicy.KEEP_RIGHT:
                o1[k] = v2;
                return null;
            case JsonMergePolicy.CONFLICT:
                if (v1 !== v2) {
                    return new Error("Conflict on key " + k);
                }
                return null;
            default:
        }
    }
    return new Error("Cannot merge type " + t1 + " with type " + t2);
}
/**
 * @brief Merge two objects.
 * @private
 * @param {any} o1 The left value.
 * @param {any} o2 The right value.
 * @param {JsonMergePolicy} policy The merge policy.
 * @param {(j1: any, j2: any) => boolean} arrayComparator The element
 *     comparator.
 * @return {Error | null} null in case of success.
 */
function _mergeTwoObjects(o1, o2, policy, arrayComparator) {
    const keys2 = Object.keys(o2);
    for (let i = 0; i < keys2.length; ++i) {
        const k = keys2[i];
        const v1 = o1[k];
        const v2 = o2[k];
        if (typeof v1 === "undefined") {
            o1[k] = v2;
            continue;
        }
        const res = _mergeObjectHelper(o1, k, v1, v2, policy, arrayComparator);
        if (res !== null)
            return res;
    }
    return null;
}
/**
 * @brief Default comparator.
 * @param {any} _j1 The first object.
 * @param {any} _j2 The second object.
 * @return {boolean} Always false.
 */
function appendArrayComparator(_j1, _j2) {
    return false;
}
/**
 * @brief Merge all the given JSONs.
 * @param {Array<any>} jsons The list of JSONs to merge.
 * @param {JsonMergePolicy} policy The merge policy.
 * @param {(j1: any, j2: any) => boolean} arrayComparator The comparator to use.
 *     Default is appendArrayComparator.
 * @return {Promise<any>} A new JSON, as result.
 */
function mergeJson(jsons, policy = JsonMergePolicy.KEEP_LEFT, arrayComparator = appendArrayComparator) {
    if (jsons.length === 0)
        return Promise.resolve({});
    const first = jsons[0];
    if (Array.isArray(first)) {
        const ret = [];
        for (let i = 0; i < jsons.length; ++i) {
            const res = _mergeTwoArrays(ret, jsons[i], policy, arrayComparator);
            if (res !== null)
                return Promise.reject(res);
        }
        return Promise.resolve(ret);
    }
    else if (typeof first === "object") {
        const ret = {};
        for (let i = 0; i < jsons.length; ++i) {
            const res = _mergeTwoObjects(ret, jsons[i], policy, arrayComparator);
            if (res !== null)
                return Promise.reject(res);
        }
        return Promise.resolve(ret);
    }
    else if (jsons.length === 1
        && (typeof jsons[0] === "number"
            || typeof jsons[0] === "string"
            || typeof jsons[0] === "boolean")) {
        return Promise.resolve(jsons[0]);
    }
    return Promise.reject(new Error("Unable to perform the merge."));
}
exports.mergeJson = mergeJson;
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