mframejs/src/mframejs/binding/array/classArrayObserverCreator.ts

simple framework

import { ClassArrayObserver } from './classArrayObserver';
import { Cache } from '../../utils/exported';
import { IBindingContext } from '../../interface/exported';

// helper class (its faster this way)
const emptyObject = class {
    // nothing
};



/*
 * creates a observer for array on class/object
 * classRef.__observerArray[this.keyBlock]
 *
 */
export class ClassArrayObserverCreator {
    private static classRef: any;
    private static keyParts: any;
    private static keyNo: any;
    private static keyBlock: any;



    /**
      * create
      *
      */
    public static create(_class: IBindingContext, observerKey: string, caller: any) {

        this.classRef = _class && _class.$context;

        this.keyParts = Cache.keyMaps.getCreate(observerKey);

        this.keyNo = 0;
        this.keyBlock = this.keyParts[this.keyNo];

        ClassArrayObserverCreator.processKeys(caller);
        ClassArrayObserverCreator.clear();

    }



    /**
     * removes the observer
     *
     */
    public static remove(_class: IBindingContext, observerKey: string, caller: any) {

        this.classRef = _class.$context;
        this.keyParts = Cache.keyMaps.getCreate(observerKey);
        this.keyNo = 0;
        this.keyBlock = this.keyParts[this.keyNo];

        ClassArrayObserverCreator.removeKeys(caller);
        ClassArrayObserverCreator.clear();

    }



    /**
     * clear class
     *
     */
    private static clear() {
        this.classRef = null;
        this.keyParts = null;
        this.keyNo = null;
        this.keyBlock = null;
    }



    /**
     * sets next key
     *
     */
    private static nextKey() {
        this.keyNo++;
        this.keyBlock = this.keyParts[this.keyNo];
    }



    /**
     * added oberserver properties to object/class
     *
     */
    private static processKeys(caller: any) {

        // add "__obeserver" prop if it does not exist
        if (!this.classRef.__observerArray) {
            Object.defineProperty(this.classRef, '__observerArray', {
                writable: true,
                configurable: true,
                value: new emptyObject()
            });
        }

        // create observer
        if (!this.classRef.__observerArray[this.keyBlock]) {
            this.classRef.__observerArray[this.keyBlock] = new ClassArrayObserver(this.classRef, this.keyBlock);
            this.classRef.__observerArray[this.keyBlock].subscribe(caller);
        } else {
            this.classRef.__observerArray[this.keyBlock].subscribe(caller);
            this.classRef.__observerArray[this.keyBlock].observe();
        }

        // if not next
        if (this.keyNo !== this.keyParts.length - 1 && this.keyParts.length > 1) {

            if (this.classRef) {
                this.classRef = this.classRef[this.keyBlock];
            }

            this.nextKey();
            if (this.classRef) {
                this.processKeys(caller);
            }
        }
    }



    /**
     * removes the caller
     *
     */
    private static removeKeys(caller: any) {


        // unsubescribe
        if (this.classRef.__observerArray) {
            if (this.classRef.__observerArray[this.keyBlock]) {
                this.classRef.__observerArray[this.keyBlock].unsubscribe(caller);
            }
        }


        // if not next
        if (this.keyNo !== this.keyParts.length - 1 && this.keyParts.length > 1) {

            if (this.classRef) {
                this.classRef = this.classRef[this.keyBlock];
            }

            this.nextKey();
            if (this.classRef) {
                this.removeKeys(caller);
            }
        }
    }



}