mongaku/mongaku

// @flow

/**
 * A utility for deep-cloning and serializing objects with i18n-centric
 * methods pre-populate.
 */

const cloneDeepWith = require("lodash.clonedeepwith");

type i18nObject = {
    lang: string,
    gettext: (text: string) => string,
    format: (text: string, options: {}) => string,
};

// Adapted from:
// https://davidwalsh.name/javascript-arguments
const getArgs = (func: Function): Array<string> => {
    const strFunc = func.toString();
    // First match everything inside the function argument parens.
    const args =
        strFunc.match(/^function\s.*?\(([^)]*)\)/) ||
        strFunc.match(/^\(?([^)]*)\)?\s*=>/) ||
        strFunc.match(/^[^)]*\(([^)]*)\)/);

    // Split the arguments string into an array comma delimited.
    return (
        (args ? args[1] : "")
            .split(",")
            // Ensure no inline comments are parsed and trim the whitespace.
            .map(arg => arg.replace(/\/\*.*\*\//, "").trim())
            // Ensure no undefined values are added.
            .filter(arg => arg)
    );
};

const serializeValue = (i18n: i18nObject, blacklist: Array<string> = []) => (
    value: any,
    key: string,
    object: Object,
) => {
    if (blacklist.includes(key)) {
        return null;
    }

    if (typeof value === "function") {
        if (value.length === 1) {
            const args = getArgs(value);

            if (args[0] === "i18n") {
                return value.call(object, i18n) || "";
            } else if (args[0] === "lang") {
                return value.call(object, i18n.lang) || "";
            }
        } else if (value.length === 0) {
            return value.call(object) || "";
        }
    }

    return undefined;
};

const cloneObject = (
    object: {},
    i18n: i18nObject,
    blacklist: Array<string> = [],
) => {
    return cloneDeepWith(object, serializeValue(i18n, blacklist));
};

const cloneModel = (model: {toJSON: () => Object}, i18n: i18nObject) => {
    const serialize = serializeValue(i18n);
    const result = model.toJSON();

    if (model.constructor.schema) {
        for (const key in model.constructor.schema.methods) {
            result[key] = serialize(model[key], key, model);
        }
    }

    return result;
};

module.exports = {cloneObject, cloneModel};