Run Code when PyScript Has Finished

The PyScript loading cycle does many things - loads plugins, instantiates the <py-script> and <py-repl> tags, attachs event listeners and so on. To cause something to happen once this entire process is complete, the easiest way is to use a plugin. Plugins can be written in Python or JavaScript; we'll show examples of both.

JavaScript

To run run some JavaScript code when PyScript completes, create a new .js file with a name of your choice. Here, we'll use example.js. In this file, add the following:

export default class ExamplePlugin { // the name of the class is unimportant
    afterStartup(interpreter){
        console.log("Hello, world!") // your code here 
    }
}

Then add this file to the plugins list inside the <py-config> tag, like so:

<py-config>
    plugins = ['example.js']
</py-config>

Python

To run run some Python code when PyScript completes, create a new .py file with a name of your choice. Here, we'll use example.py. In this file, add the following:

from pyscript import Plugin # A base class for plugins

class ExamplePlugin(Plugin): # The name of the class is unimportant
    def afterSetup(self, interpreter):
        print("Hello, world!")    

plugin = ExamplePlugin() # The object named 'plugin' will have its methods called

The Interpreter Argument

In both cases, the interpreter argument is an interpreter_client object, which wraps the actual interpreter. Key methods include run() for executing Python code. See the previous link for the source and details.