Transcrypt | Python 3.9 to JavaScript compiler - Lean, fast, open! - | Compiler library

What version of Transcrypt are you using? Wasn't able to replicate the error using Python 3.9.0 and Transcrypt 3.9.0. You can check like this (Win):

I googled that error and found this promising GitHub issue comment which says

You can now compile without minification, so without Java by using the -n switch.

So, try

The short answer is no, for example see Main differences with CPython:

Web batteries: Seamless access to any existing JavaScript library has been favored over inclusion of many Python libraries in the distribution. There are some exceptions to this rule, e.g. math, cmath, random, itertools, re, time, datetime and turtle, and some more may follow, but in general the accent is on libraries that are relevant in the browser.

To send email from a browser, you'll probably call a third party service using ajax as in these stackoverflow answers.

To do so from the server side, instead of using js compiled from python in node, you would probably prefer to use python directly.

import declarations may only appear at top level of a module

is fairly clear: You're not loading the script as a module, so you can't use import. Add type="module" to the script tag. (But be sure that your target browsers support modules -- all modern major ones do, but you don't have to go more than a few versions back in some before module support isn't there.)

missing { before try block

You have

You cannot do this. IE does not understand the type="module" attribute.

Instead use rollup.js and Babel to bundle your module into an old style script mystuff_incl_ie.js and load this with the normal script tag:

The full standard library has not been ported to Transcrypt yet, the json library included. In most cases you can get around this by using a JavaScript equivalent library to support whatever you are trying to accomplish, and they can be called directly from your Python code. But Transcrypt doesn't automatically do this library mapping for you, so you'll have to explicitly import the JavaScript library to use it.

Since Python dictionaries are converted to JavaScript objects with Transcrypt, you may be able to just use the JSON data as-is. Otherwise you can call the built-in JSON.parse() and JSON.stringify() directly with no imports necessary.

You use very, very strange method to create string.

You don't need to use print() to keep it as string in variable - so you don't need io.String()

More popular is to keep all strings on list and later join them using "\n"

I don't believe Transcrypt has the Python urllib library available. You will need to use a corresponding JavaScript library instead. I prefer axios, but you can also just use the built in XMLHttpRequest() or window.fetch()

Here is a Python function you can incorporate that uses window.fetch():

Some things you could try.

1. Make sure it is html 5 by adding to your index.html

2. Instead of loading the file directly from the system using file://... you can use the WebViewAssetLoader this will return the mimetype https://developer.android.com/reference/kotlin/androidx/webkit/WebViewAssetLoader

3. If that does not work inside the webViewClient you could intercept the request and add the text/javascript mimetype manually: