node-microsvc-lib/lib/di_container.js

NodeJS microservice framework library

/**
 * Created by pedrosousabarreto@gmail.com on 15/Jan/2019.
 */
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.DiContainer = void 0;
const console_logger_1 = require("./console_logger");
class DiContainer {
    constructor(logger) {
        this._dependencies = new Map();
        this._factories = new Map();
        if (!logger)
            this._di_logger = new console_logger_1.ConsoleLogger().create_child({ class: "DiContainer" });
        else
            this._di_logger = logger.create_child({ class: "DiContainer" });
    }
    register_factory(name, factory) {
        this._check_duplicate_name(name);
        // TODO check that it implements IDiFactory
        this._di_logger.info("DI Container - registering factory: %s", name);
        this._factories.set(name, factory);
    }
    register_dependency(name, dep) {
        this._check_duplicate_name(name);
        this._di_logger.info("DI Container - registering dependency: %s", name);
        this._dependencies.set(name, dep);
    }
    ;
    has(name) {
        return (this._dependencies.has(name) || this._factories.has(name));
    }
    get(name) {
        name = name.trim();
        if (!this._dependencies.has(name)) {
            const uninitialised_factory = this._factories.get(name);
            if (uninitialised_factory) {
                this._di_logger.info("DI Container - injecting factory: %s", name);
                this._dependencies.set(name, this._inject(uninitialised_factory));
            }
            if (!this._dependencies.has(name))
                throw new Error("DI Container - cannot find module: " + name);
        }
        return this._dependencies.get(name);
    }
    _check_duplicate_name(name) {
        if (!this.has(name))
            return;
        const err = new Error(`Di Container - already has an object named ${name}`);
        this._di_logger.fatal(err);
        throw err;
    }
    _inject(factory) {
        // @ts-ignore
        let ctor = factory.prototype.constructor.toString();
        let args_list = ctor.match(/constructor\s?\(([^)]*)\)/).splice(1)[0];
        if (!args_list)
            return new factory();
        // args_list = args_list.replace(" ", "");
        let args_array = args_list.split(",");
        // if (args_array.length <= 0)
        // 	return new (<any>factory)();
        // map them to the dependencies/factories
        let args = args_array.map((dependency) => {
            return this.get(dependency);
        });
        // instantiate and return
        return new factory(...args);
    }
}
exports.DiContainer = DiContainer;
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