@hemjs/gather/dist/gather.js

A lightweight library for collecting and merging configuration from multiple sources

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Gather = void 0;
const notions_1 = require("@hemjs/notions");
const uid_1 = require("uid");
const utils_1 = require("./utils");
/**
 * Gather configuration generated by configuration providers.
 */
class Gather {
    /**
     * Create a new Gather instance.
     * @param providers the configuration providers
     */
    constructor(providers = []) {
        this.config = this.loadFromProviders(providers);
    }
    /**
     * Returns merged configurations object
     * @returns merged configurations object
     */
    getMerged() {
        return this.config;
    }
    /**
     * Iterate providers, merging config from each with the previous.
     * @param providers an array of configuration providers
     * @returns merged configurations object
     */
    loadFromProviders(providers) {
        const merged = {};
        for (const provider of providers) {
            const instance = this.resolveProvider(provider);
            if (this.isModuleProvider(instance)) {
                (0, utils_1.merge)(merged, instance.register());
            }
            else if ((0, notions_1.isPlainObject)(instance)) {
                (0, utils_1.merge)(merged, instance);
            }
        }
        return merged;
    }
    /**
     * Resolve a provider.
     * @param providers an array of configuration providers
     * @returns merged configurations object
     */
    resolveProvider(provider) {
        if ((0, notions_1.isObject)(provider)) {
            return provider;
        }
        if ((0, notions_1.isClass)(provider)) {
            const typeProvider = provider;
            return new typeProvider();
        }
        if (!(0, notions_1.isFunction)(provider)) {
            throw new Error('Invalid config provider');
        }
        const metatype = this.mapToClass(provider);
        return new metatype();
    }
    /**
     * Check if the given provider has the register method.
     * @param provider the provider to check
     * @returns whether the given provider has the register method
     */
    isModuleProvider(provider) {
        return (0, notions_1.isFunction)(provider.register);
    }
    /**
     * Map a function to a class.
     * @param instance the function to map
     * @returns the resulting class
     */
    mapToClass(instance) {
        return this.assignToken(class {
            constructor() {
                this.register = (...params) => {
                    return instance(...params);
                };
            }
        });
    }
    /**
     * Assign unique token to a metatype.
     * @param metatype the metatype to assign token
     * @param token the unique token
     * @returns the resulting metatype
     */
    assignToken(metatype, token = (0, uid_1.uid)(21)) {
        Object.defineProperty(metatype, 'name', { value: token });
        return metatype;
    }
}
exports.Gather = Gather;