loadOpencv sometimes never resolves

[PeterBenko]

The call to Mirada.loadOpencv never resolves if opencvJsLocation points to a opencv.js that loads opencv_js.wasm. (self-compiled 4.4.0 if that matters).

This is due to the fact that cv.onRuntimeInitialized gets assigned only after the "load" callback here, at which point opencv.js already checks the global cv variable, and assigns a new empty object to its Module variable and then doesn't see an "onRuntimeInitialized" property to call when done with the initialization.

[Rufflewind]

Seems like the proper way to detect if it's loaded is by defining a Modules directly: https://stackoverflow.com/a/56978454

const Module = {};
function ... {
  return new Promise((resolve, reject) => {
    Module.onRuntimeInitialized = resolve;
    /* create script element ... */
  }
}

[fushihara]

I will share information on this issue.

I made the method in Promise so that I can easily get the initialized instance, but for some reason Promise did not solve the problem.

import cv from '@techstark/opencv-js';
export async function getReadyCv() {
  await new Promise<void>(resolve => {
    cv.onRuntimeInitialized = () => {
      resolve();
    }
  })
  return cv;
}

The problem seems to be that the Module already implements a method named "then", and I have some doubts about the javascript behavior, but anyway, I modified it as follows and it works

import cv from '@techstark/opencv-js';
export async function getReadyCv() {
  await new Promise<void>(resolve => {
    cv.onRuntimeInitialized = () => {
      resolve();
    }
  })
  return {cv:cv};
}