Export Runtime from PyScript Module (#868)

* export 'pyscript' JS module with runtime attribute, to allow accessing (Pyodide) runtime and globals from JS.
* add docs to explain the js module
* add integration tests for the js module

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

pyscriptjs/rollup.config.js

@@ -27,7 +27,7 @@ export default {
     sourcemap: true,
     format: "iife",
     inlineDynamicImports: true,
-    name: "app",
+    name: "pyscript",
     file: "build/pyscript.js",
     },
     {

pyscriptjs/src/main.ts

@@ -57,6 +57,7 @@ class PyScriptApp {
 
     config: AppConfig;
     loader: PyLoader;
+    runtime: Runtime;
 
     // lifecycle (1)
     main() {
@@ -111,13 +112,13 @@ class PyScriptApp {
                       "Only the first will be used");
         }
         const runtime_cfg = this.config.runtimes[0];
-        const runtime: Runtime = new PyodideRuntime(this.config, runtime_cfg.src,
+        this.runtime = new PyodideRuntime(this.config, runtime_cfg.src,
                                                     runtime_cfg.name, runtime_cfg.lang);
         this.loader.log(`Downloading ${runtime_cfg.name}...`);
         const script = document.createElement('script'); // create a script DOM node
-        script.src = runtime.src;
+        script.src = this.runtime.src;
         script.addEventListener('load', () => {
-            void this.afterRuntimeLoad(runtime);
+            void this.afterRuntimeLoad(this.runtime);
         });
         document.head.appendChild(script);
     }
@@ -209,3 +210,5 @@ globalExport('pyscript_get_config', pyscript_get_config);
 // main entry point of execution
 const globalApp = new PyScriptApp();
 globalApp.main();
+
+export const runtime = globalApp.runtime

pyscriptjs/tests/integration/test_04_runtime.py

@@ -0,0 +1,42 @@
+from .support import PyScriptTest
+
+
+class TestRuntimeAccess(PyScriptTest):
+    """Test accessing Python objects from JS via pyscript.runtime"""
+
+    def test_runtime_python_access(self):
+        self.pyscript_run(
+            """
+            <py-script>
+                x = 1
+                def py_func():
+                    return 2
+            </py-script>
+            """
+        )
+
+        self.page.add_script_tag(
+            content="""
+        console.log(`x is ${pyscript.runtime.globals.get('x')}`);
+        console.log(`py_func() returns ${pyscript.runtime.globals.get('py_func')()}`);
+        """
+        )
+
+        assert self.console.log.lines == [
+            self.PY_COMPLETE,
+            "x is 1",
+            "py_func() returns 2",
+        ]
+
+    def test_runtime_script_execution(self):
+        """Test running Python code from js via pyscript.runtime"""
+        self.pyscript_run("")
+
+        self.page.add_script_tag(
+            content="""
+        const interpreter = pyscript.runtime.interpreter;
+        interpreter.runPython('console.log("Interpreter Ran This")');
+        """
+        )
+
+        assert self.console.log.lines == [self.PY_COMPLETE, "Interpreter Ran This"]