winterspec/dist/lib/async-work-tracker.js

Write Winter-CG compatible routes with filesystem routing and tons of features

import EventEmitter from "node:events";
/**
 * This is effectively a Promise that can be resolved multiple times in different scopes without messily holding references to the resolve function.
 */
export class AsyncWorkTracker extends EventEmitter {
    constructor() {
        super(...arguments);
        this.state = "idle";
    }
    /**
     * If work is still pending, this waits for the next work result. If work is already resolved, it returns the last result.
     */
    async waitForResult() {
        if (this.state === "pending" || !this.lastResult) {
            return new Promise((resolve) => {
                this.once("result", resolve);
            });
        }
        if (!this.lastResult) {
            throw new Error("No last result (this should never happen)");
        }
        return this.lastResult;
    }
    /**
     * Call this when you start async work.
     */
    beginAsyncWork() {
        this.state = "pending";
    }
    /**
     * Call this when the async work is done with the result.
     */
    finishAsyncWork(result) {
        this.state = "resolved";
        this.emit("result", result);
        this.lastResult = result;
    }
}