@dhmk/atom/esm/atoms/computed.js

Lightweight mobx-like observable values, computed values and side-effects

var __assign = (this && this.__assign) || function () {
    __assign = Object.assign || function(t) {
        for (var s, i = 1, n = arguments.length; i < n; i++) {
            s = arguments[i];
            for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
                t[p] = s[p];
        }
        return t;
    };
    return __assign.apply(this, arguments);
};
import { removeAtom, useAtom } from "../shared";
import { Id, AtomState, defaultAtomOptions, } from "../types";
import { runtime } from "../runtime";
var ComputedAtom = /** @class */ (function () {
    function ComputedAtom(fn, options) {
        this.fn = fn;
        this.observers = new Map();
        this.deps = Array();
        this.prevDeps = Array();
        this.prevDepsIndex = 0;
        this.runId = new Id();
        this.versionId = new Id();
        this.isObserved = false;
        this.depsForUnobserved = new Set();
        this.isError = false;
        this.state = AtomState.Stale;
        this.depsVersions = Array();
        this.options = __assign(__assign({}, defaultAtomOptions), options);
    }
    ComputedAtom.prototype.invalidate = function (state, isValueAtom) {
        var oldState = this.state;
        if (state > this.state)
            this.state = state;
        if (oldState === AtomState.Actual)
            this.observers.forEach(function (_, a) {
                return a.invalidate(AtomState.PossiblyStale, false);
            });
    };
    ComputedAtom.prototype.calculate = function () {
        this.prevDeps = this.deps;
        this.deps = [];
        this.prevDepsIndex = 0;
        this.runId = new Id();
        if (!this.isObserved && runtime.currentAtom) {
            this.isObserved = true;
            var onBO = this.options.onBecomeObserved;
            if (onBO)
                runtime.addEffect({ actualize: onBO });
        }
        if (!this.isObserved)
            this.depsForUnobserved = new Set();
        var nextValue;
        var isError;
        var prevAtom = runtime.currentAtom;
        runtime.currentAtom = this;
        try {
            nextValue = this.fn();
        }
        catch (e) {
            isError = true;
            nextValue = e;
        }
        runtime.currentAtom = prevAtom;
        if (!this.isObserved)
            this.deps = Array.from(this.depsForUnobserved);
        this.depsVersions.length = this.deps.length;
        for (var i = 0; i < this.deps.length; ++i) {
            var dep = this.deps[i];
            dep.runId = this.runId;
            this.depsVersions[i] = dep.versionId;
        }
        for (var i = this.prevDepsIndex; i < this.prevDeps.length; ++i) {
            var a = this.prevDeps[i];
            if (a.runId !== this.runId)
                removeAtom(a, this);
        }
        this.prevDeps = [];
        this.state = this.isObserved ? AtomState.Actual : AtomState.PossiblyStale;
        if (!this.options.equals(nextValue, this.value)) {
            this.value = nextValue;
            this.isError = isError;
            this.versionId = new Id();
            this.observers.forEach(function (_, a) { return a.invalidate(AtomState.Stale, false); });
        }
    };
    ComputedAtom.prototype.actualize = function () {
        if (this.state === AtomState.Actual)
            return;
        if (this.state === AtomState.PossiblyStale) {
            for (var i = 0; i < this.deps.length; ++i) {
                var dep = this.deps[i];
                dep.actualize();
                if (dep.versionId !== this.depsVersions[i]) {
                    this.state = AtomState.Stale;
                    break;
                }
            }
        }
        if (this.state === AtomState.PossiblyStale)
            this.state = AtomState.Actual;
        if (this.state === AtomState.Stale)
            this.calculate();
    };
    ComputedAtom.prototype.get = function () {
        this.actualize();
        useAtom(this);
        if (this.isError)
            throw this.value;
        return this.value;
    };
    ComputedAtom.prototype.toJSON = function () {
        return this.get();
    };
    ComputedAtom.prototype.dispose = function () {
        if (this.isObserved) {
            this.isObserved = false;
            var onBUO = this.options.onBecomeUnobserved;
            if (onBUO)
                runtime.addEffect({ actualize: onBUO });
            for (var i = 0; i < this.deps.length; ++i) {
                removeAtom(this.deps[i], this);
            }
            this.state = AtomState.Stale;
        }
    };
    return ComputedAtom;
}());
export { ComputedAtom };