Calling JS library function fails stating object.clone is not a function

[BaiqingL]

I am trying to create a wrapper around the @smogon/calc library, and following its example essentially I am trying to re-implement this code-snippet with the python wrapper:

import {calculate, Generations, Pokemon, Move} from '@smogon/calc';

const gen = Generations.get(5); // alternatively: const gen = 5;
const result = calculate(
  gen,
  new Pokemon(gen, 'Gengar', {
    item: 'Choice Specs',
    nature: 'Timid',
    evs: {spa: 252},
    boosts: {spa: 1},
  }),
  new Pokemon(gen, 'Chansey', {
    item: 'Eviolite',
    nature: 'Calm',
    evs: {hp: 252, spd: 252},
  }),
  new Move(gen, 'Focus Blast')
);

Here is what I am doing in python

from javascript import require
damage_calc = require('@smogon/calc')
generation = damage_calc.Generations.get(5)
attacker = damage_calc.Pokemon(generation, 'Gengar', {
    'item': 'Choice Specs',
    'nature': 'Timid',
    'evs': {'spa': 252},
    'boosts': {'spa': 1},
  })
defender = damage_calc.Pokemon(generation, 'Chansey', {
    'item': 'Eviolite',
    'nature': 'Calm',
    'evs': {'hp': 252, 'spd': 252},
  })
move = damage_calc.Move(generation, 'Focus Blast')
damage = damage_calc.calculate(generation, attacker, defender, move)

Object creations works until I get to the damage line, the error states that

☕  JavaScript Error  Call to 'calculate' failed:
> damage = damage_calc.calculate(generation, attacker, defender, move)
  at <module> (/tmp/ipykernel_10306/2465370261.py:2)
> 

... across the bridge ...

  at Pipe.onStreamRead (node:internal/stream_base_commons:191:23)
  at Readable.push (node:internal/streams/readable:390:5)
  at readableAddChunkPushByteMode (node:internal/streams/readable:510:3)
  at addChunk (node:internal/streams/readable:559:12)
  at Socket.emit (node:events:520:28)
  at Socket.<anonymous> (/home/andy/.conda/envs/dev/lib/python3.12/site-packages/javascript/js/bridge.js:292:18)
  at Bridge.onMessage (/home/andy/.conda/envs/dev/lib/python3.12/site-packages/javascript/js/bridge.js:231:25)
  at Bridge.call (/home/andy/.conda/envs/dev/lib/python3.12/site-packages/javascript/js/bridge.js:136:42)
  at Object.calculate (/home/andy/.conda/envs/dev/lib/python3.12/site-packages/javascript/js/node_modules/@smogon/calc/dist/index.js:46:39)
  at calculate (/home/andy/.conda/envs/dev/lib/python3.12/site-packages/javascript/js/node_modules/@smogon/calc/dist/calc.js:23:45)
> return MECHANICS[gen.num](gen, attacker.clone(), defender.clone(), move.clone(), field ? field.clone() : new field_1.Field());
🌉 TypeError: attacker.clone is not a function

It looks like the way I am creating the Pokemon object is wrong, as it doesn't seem to have the clone() function that it's supposed to. How am I supposed to create it properly?

[extremeheat]

Hi,

Your problem seems to be due to the Pokemon and Move objects not being proper ES6 classes (with class syntax), and are instead ES5 classes (standard functions with object extension behavior). This is usually due to bundlers/transpilers trying to support legacy JS engines that don't support JS features from 2015+. JSPyBridge will automatically call ES6 classes with new as it can detect them, but otherwise for old code you need to use the .new pseudo method to act similar to new <object> syntax in JS. This is mention under the "ES5 class" part of the readme doc.

There does seem to be a bug with .new handling, but it should be fixed with #137

[extremeheat]

Can you please checkout if

pip install https://github.com/extremeheat/JSPyBridge/archive/fix-es5-class.zip

fixes your issue?

Seems to work per
https://colab.research.google.com/gist/extremeheat/00c880b7d77fdc8dab90080e50e91c0f/jspybridge-136.ipynb

[BaiqingL]

Hmm, upon running that install I seem to get this error:

☕  JavaScript Error  Call to '' failed:
> attacker = damage_calc.Pokemon.new(generation, 'Gengar', {
  at <module> (/home/andy/Documents/damage-calc-py-wrapper/run_print.py:5)
> 

... across the bridge ...

  at Pipe.onStreamRead (node:internal/stream_base_commons:191:23)
  at Readable.push (node:internal/streams/readable:390:5)
  at readableAddChunkPushByteMode (node:internal/streams/readable:510:3)
  at addChunk (node:internal/streams/readable:559:12)
  at Socket.emit (node:events:520:28)
  at Socket.<anonymous> (/home/andy/.conda/envs/dev/lib/python3.12/site-packages/javascript/js/bridge.js:292:18)
  at Bridge.onMessage (/home/andy/.conda/envs/dev/lib/python3.12/site-packages/javascript/js/bridge.js:231:25)
  at Bridge.init (/home/andy/.conda/envs/dev/lib/python3.12/site-packages/javascript/js/bridge.js:128:68)
  TypeError: this.m[ffid] is not a constructor
> ^
🌉 TypeError: this.m[ffid] is not a constructor

[extremeheat]

You are probably not using the correct version of the package, that is what #137 is fixing, please test on the linked notebook any code you modified to ensure a clean environment. If you can reproduce please provide a colab or link to notebook.

[BaiqingL]

I see, this works now, thanks.

[extremeheat]

Should be fixed in v1.2.1