movex-core-util/src/lib/Observable/Observable.js

Movex Core Util is the library of utilities for Movex

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Observable = void 0;
const ts_pubsy_1 = require("ts-pubsy");
const misc_1 = require("../misc");
class Observable {
    constructor(_state) {
        this._state = _state;
        this.pubsy = new ts_pubsy_1.Pubsy();
    }
    get() {
        return this._state;
    }
    onUpdate(fn) {
        return this.pubsy.subscribe('onUpdate', fn);
    }
    update(nextStateGetter) {
        this._state = Observable.getNextStateFrom(this._state, nextStateGetter);
        // TODO: Should it only call onUpdate when there actually is an update??
        //  Or should I leave that to the implementation
        this.pubsy.publish('onUpdate', this._state);
        return this;
    }
    /**
     * Ability to transform the state
     *
     * @param mapFn
     * @returns
     */
    map(mapFn) {
        const $next = new Observable(mapFn(this.get()));
        this.onUpdate((nextRootState) => {
            $next.update(mapFn(nextRootState));
        });
        return $next;
    }
}
exports.Observable = Observable;
Observable.getNextStateFrom = (prev, a) => (0, misc_1.isFunction)(a) ? a(prev) : a;
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