Table of Contents

• Standard Module: promise
• Promise
• promise(duration) implements Promise
• Implementation

Standard Module: promise

To use the promise module and the Promise interface in a HipHop program, import the JavaScript module with:

import { promise, Promise } from "@hop/hiphop/modules/promise.js";

The promise HipHop module maps JavaScript promises to HipHop signals. It enables to spawn a JavaScript promise which upon resolution or rejection emits a HipHop signal.

Promise

The Promise interface declares the following HipHop signals:

• out value, whether it resolves or rejects, a Promise HipHop module emits a single signal. That signal is an object with two attributes: {res: resolution-value, rej: rejection-value}.

promise(duration) implements Promise

A HipHop promise module is an asynchronous tasks that run in the background of the application. When it resolves or rejects, it emits its signal value. Example:

// emits v with the value { resolve: "yep", reject: false }
run promise(new Promise((res, rej) => res("yep")))) { v as value }; 

★ Example: promise-mod.hh.js

import * as hh from "@hop/hiphop";
import { promise } from "@hop/hiphop/modules/promise.js";
import { format } from "util";


hiphop module prg(resolve) {
   out STATUS;
   signal v;

   fork {
      run promise(new Promise((res, rej) => res(45))) { v as value };
   } par {
      await (v.now);
      emit STATUS(v.nowval.res);
   }

   pragma { resolve(false); }
}

export const mach = new hh.ReactiveMachine(prg);
mach.outbuf = "";
mach.debug_emitted_func = emitted => {
   mach.outbuf += format(emitted) + "\n";
};
mach.batchPromise = new Promise((res, rej) => mach.init(res));

mach.react();

Implementation

• JavaScript implementation: promise.hh.js
• TypeScript type declaration: promise.d.ts

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