overmind/es/derived.js

Frictionless state management

import { EventType } from "./internalTypes.js";
import { IS_PROXY, TrackStateTree } from "proxy-state-tree";

//#region src/derived.ts
const IS_DERIVED = Symbol("IS_DERIVED");
const IS_DERIVED_CONSTRUCTOR = Symbol("IS_DERIVED_CONSTRUCTOR");
var Derived = class {
	constructor(cb) {
		this.cb = cb;
		this.isDirty = true;
		this.updateCount = 0;
		const boundEvaluate = this.evaluate.bind(this);
		if (process.env.NODE_ENV === "development") boundEvaluate.dispose = () => {
			this.disposeOnMutation();
		};
		boundEvaluate[IS_DERIVED] = true;
		return boundEvaluate;
	}
	runScope(tree, path) {
		const parent = path.slice(0, path.length - 1).reduce((curr, key) => curr[key], tree.state);
		return this.cb(parent, tree.state);
	}
	evaluate(eventHub, tree, proxyStateTree, path) {
		if (!this.disposeOnMutation) this.disposeOnMutation = proxyStateTree.onMutation((_, paths, flushId) => {
			if (typeof path.reduce((aggr, key) => aggr && aggr[key], proxyStateTree.sourceState) !== "function") {
				this.disposeOnMutation();
				return;
			}
			if (this.isDirty) return;
			for (const mutationPath of paths) if (this.paths.has(mutationPath)) {
				this.isDirty = true;
				eventHub.emitAsync(EventType.DERIVED_DIRTY, {
					derivedPath: path,
					path: mutationPath,
					flushId
				});
				return;
			}
		});
		if (this.isDirty || this.previousProxifier !== tree.proxifier) {
			const getPaths = tree.trackPaths();
			this.value = this.runScope(tree, path);
			this.isDirty = false;
			this.paths = getPaths();
			if (process.env.NODE_ENV === "development") {
				eventHub.emitAsync(EventType.DERIVED, {
					path,
					paths: Array.from(this.paths),
					updateCount: this.updateCount,
					value: this.value
				});
				this.updateCount++;
			}
		}
		if (tree instanceof TrackStateTree) for (const path$1 of this.paths) {
			tree.addTrackingPath(path$1);
			tree.trackPathListeners.forEach((cb) => cb(path$1));
		}
		this.previousProxifier = tree.proxifier;
		if (this.value && this.value[IS_PROXY]) return proxyStateTree.rescope(this.value, tree);
		return this.value;
	}
};

//#endregion
export { Derived, IS_DERIVED, IS_DERIVED_CONSTRUCTOR };
//# sourceMappingURL=derived.js.map