Add a script to extract strings from javascript

client/extract-translatable-strings.js

@@ -0,0 +1,32 @@
+// eslint-disable-next-line @typescript-eslint/no-var-requires
+const { GettextExtractor, JsExtractors } = require('gettext-extractor');
+
+const extractor = new GettextExtractor();
+
+extractor
+  .createJsParser([
+    JsExtractors.callExpression('gettext', {
+      arguments: {
+        text: 0,
+        context: 1,
+      },
+    }),
+    JsExtractors.callExpression('gettext_noop', {
+      arguments: {
+        text: 0,
+        context: 1,
+      },
+    }),
+    JsExtractors.callExpression('ngettext', {
+      arguments: {
+        text: 1,
+        textPlural: 2,
+        context: 3,
+      },
+    }),
+  ])
+  .parseFilesGlob('./src/**/*.@(ts|js|tsx|jsx)');
+
+extractor.savePotFile('../wagtail/admin/locale/en/LC_MESSAGES/djangojs.po');
+
+extractor.printStats();

package.json

@@ -74,6 +74,7 @@
     "enzyme-to-json": "^3.6.2",
     "eslint": "^8.5.0",
     "expose-loader": "^3.1.0",
+    "gettext-extractor": "^3.5.3",
     "jest": "^26.6.3",
     "mini-css-extract-plugin": "^2.4.5",
     "postcss": "^8.4.7",

scripts/rebuild-translation-sources.sh

@@ -8,3 +8,8 @@ do
     django-admin makemessages --locale=en
     popd
 done
+
+# Extract translatable strings from JavaScript
+pushd ../client
+node extract-translatable-strings.js
+popd