@nivinjoseph/n-ject/src/component-registration.ts

IOC container

import { given } from "@nivinjoseph/n-defensive";
import { Disposable } from "@nivinjoseph/n-util";
import { injectionsKey } from "./inject.js";
import { Lifestyle } from "./lifestyle.js";

// internal
export class ComponentRegistration implements Disposable
{
    private readonly _key: string;
    private readonly _component: Function | object;
    private readonly _lifestyle: Lifestyle;
    private readonly _dependencies: ReadonlyArray<string>;
    private readonly _aliases: ReadonlyArray<string>;
    private _isDisposed = false;
    private _disposePromise: Promise<void> | null = null;


    public get key(): string { return this._key; }
    public get component(): Function | object { return this._component; }
    public get lifestyle(): Lifestyle { return this._lifestyle; }
    public get dependencies(): ReadonlyArray<string> { return this._dependencies; }
    public get aliases(): ReadonlyArray<string> { return this._aliases; }


    public constructor(key: string, component: Function | object, lifestyle: Lifestyle, ...aliases: Array<string>)
    {
        given(key, "key").ensureHasValue().ensureIsString();
        given(component, "component").ensureHasValue();
        given(lifestyle, "lifestyle").ensureHasValue().ensureIsEnum(Lifestyle);
        given(aliases, "aliases").ensureHasValue().ensureIsArray()
            // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
            .ensure(t => t.every(u => u != null), "alias cannot null")
            .ensure(t => t.every(u => u !== key), "alias cannot be the same as key")
            .ensure(t => t.length === t.map(u => u.trim()).distinct().length, "duplicates detected");

        this._key = key;
        this._component = component;
        this._lifestyle = lifestyle;
        this._dependencies = this._getDependencies();
        this._aliases = [...aliases.map(t => t.trim())];
    }


    public async dispose(): Promise<void>
    {
        if (!this._isDisposed)
        {
            this._isDisposed = true;

            this._disposePromise = this._disposeComponent();
        }

        return this._disposePromise!;
    }

    private async _disposeComponent(): Promise<void>
    {
        // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
        if (typeof this._component !== "function" && (<Disposable>this._component).dispose
            && typeof (<Disposable>this._component).dispose === "function")
        {
            try 
            {
                await (<Disposable>this._component).dispose();
            }
            catch (error)
            {
                console.error(`Error: Failed to dispose component with key '${this._key}' of type '${(<Object>this._component).getTypeName()}'.`);
                console.error(error);
            }
        }
    }


    private _getDependencies(): Array<string>
    {
        if (this._lifestyle === Lifestyle.Instance)
            return new Array<string>();

        const metadata = (this._component as any)[Symbol.metadata];
        if (metadata == null)
            return [];

        const dependencies = metadata[injectionsKey];
        if (dependencies == null)
            return [];

        return dependencies as Array<string>;
    }


    // Borrowed from AngularJS implementation
    // private detectDependencies(): Array<string>
    // {
    //     const FN_ARG_SPLIT = /,/;
    //     const FN_ARG = /^\s*(_?)(\S+?)\1\s*$/;

    //     let dependencies = new Array<string>();

    //     let argDecl = this.extractArgs(this._component);
    //     argDecl[1].split(FN_ARG_SPLIT).forEach(arg =>
    //     {
    //         arg.replace(FN_ARG, (all, underscore, name) =>
    //         {
    //             dependencies.push(name);
    //             return undefined;
    //         });
    //     });

    //     return dependencies;
    // }

    // private stringifyFn(fn: Function): string
    // {
    //     return Function.prototype.toString.call(fn);
    // }

    // private extractArgs(fn: Function): RegExpMatchArray
    // {
    //     const ARROW_ARG = /^([^(]+?)=>/;
    //     const FN_ARGS = /^[^(]*\(\s*([^)]*)\)/m;
    //     const STRIP_COMMENTS = /((\/\/.*$)|(\/\*[\s\S]*?\*\/))/mg;

    //     let fnText = this.stringifyFn(fn).replace(STRIP_COMMENTS, "");
    //     let args = fnText.match(ARROW_ARG) || fnText.match(FN_ARGS);
    //     return args;
    // }
}