kr-observable/dist/esm/main/src/Computed.js

Adds reactivity power for your JavaScript

import { Utils } from './Utils.js';
import { Global } from './global.js';
export class Computed {
    enumerable;
    configurable;
    set;
    runId = 1;
    debug = false;
    active = false;
    deps;
    #adm;
    #property;
    #descriptor;
    #value;
    #setterValue;
    changed = false;
    computed = true;
    name;
    constructor(property, descriptor, handler) {
        this.enumerable = descriptor.enumerable;
        this.configurable = descriptor.configurable;
        this.#property = property;
        this.#descriptor = descriptor;
        this.#adm = handler.adm;
        if (descriptor.set) {
            this.set = (value) => {
                this.#descriptor.set(value);
                const prevValue = this.#setterValue;
                this.#setterValue = value;
                this.#report(prevValue, value);
            };
        }
    }
    subscriber() {
        this.changed = true;
        if (this.#adm.deps.get(this.#property)?.size === 0) {
            return;
        }
        this.compute();
    }
    run() {
        return this.#descriptor.get();
    }
    compute() {
        const prev = this.#value;
        this.#reader();
        this.#report(prev, this.#value);
    }
    #report(prevValue, newValue) {
        if (!Utils.isDeepEqual(prevValue, newValue)) {
            this.#adm.report(this.#property, newValue);
        }
        if (Global.action)
            return;
        this.#adm.batch();
    }
    #reader() {
        this.#value = Global.executor.execute(this);
    }
    get = () => {
        if (!Global.action) {
            this.#adm.batch();
        }
        if (!this.deps) {
            this.#reader();
            return this.#value;
        }
        if (this.deps?.size === 0) {
            return this.run();
        }
        if (this.changed) {
            this.changed = false;
            this.#reader();
        }
        if (this.#adm.current?.has(this)) {
            this.compute();
        }
        return this.#value;
    };
}