Property 'registerMethod' does not exist on type

[error-four-o-four]

Hey there,

as the title says, the method 'registerMethod' of the p5 prototype isn't recognized by typescript.
I encountered this issue while running p5 in instance mode. E.g.:

p5.prototype.registerMethod('init', function init(this: p5) {
  console.log('registered');
});

[asukaminato0721]

because p5.js doesn't add type for it

https://github.com/processing/p5.js/blob/cdf8d918ec8df2736ca61f0b72dfe5ccf70b61e8/src/core/main.js#L646

from the code

  registerPreloadMethod(fnString, obj) {
    // obj = obj || p5.prototype;
    if (!p5.prototype._preloadMethods.hasOwnProperty(fnString)) {
      p5.prototype._preloadMethods[fnString] = obj;
    }
  }

  registerMethod(name, m) {
    const target = this || p5.prototype;
    if (!target._registeredMethods.hasOwnProperty(name)) {
      target._registeredMethods[name] = [];
    }
    target._registeredMethods[name].push(m);
  }

registerPreloadMethod will also not exists on type.