a prototype for loading fluent strings, see phetsims/joist#992

js/load-unbuilt-fluent-strings.js

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+// Copyright 2024, University of Colorado Boulder
+
+/**
+ * A PROTOTYPE for loading unbuilt fluent strings. Meant to be a preload script, pulling in
+ * the fluent strings before the simulation is loaded.
+ *
+ * This will need to be integrated into PhET's other string loading in a more general way.
+ *
+ * @author Jesse Greenberg (PhET Interactive Simulations)
+ */
+
+( () => {
+  window.phet = window.phet || {};
+  window.phet.chipper = window.phet.chipper || {};
+
+  const repoName = phet.chipper.packageObject.name;
+
+  // Constructing the string map
+  window.phet.chipper.fluentStrings = {};
+
+  const requestFluentFile = locale => {
+    const xhr = new XMLHttpRequest();
+    xhr.open( 'GET', `${repoName}-strings_${locale}.ftl`, true );
+    xhr.responseType = 'text';
+    xhr.onload = () => {
+      if ( xhr.status === 200 ) {
+        window.phet.chipper.fluentStrings[ locale ] = xhr.response;
+      }
+    };
+
+    xhr.onerror = () => {
+
+      // Handle network errors gracefully
+      console.warn( `Network error while requesting fluent file for locale ${locale}` );
+    };
+
+    xhr.send();
+  };
+
+  // TODO: https://github.com/phetsims/joist/issues/992
+  //   How to get these? I tried using Object.keys( phet.chipper.strings ) (like availableRuntimeLocales), but that
+  //   results in many 404 errors when there ins't a file to load. load-unbuilt-strings.js pulls from babel but I
+  //   didn't undersetand that. And this prototype pulls files from the sim repo for now. These also don't
+  //   support fallback locales appropriately.
+  const localeList = [ 'en', 'es' ];
+
+  localeList.forEach( locale => {
+    requestFluentFile( locale );
+  } );
+} )();