add import.meta.env support to test runner

packages/app-scripts-react/jest/babelTransform.js

@@ -8,14 +8,13 @@
 "use strict";
 
 const babelJest = require("babel-jest");
+const importMetaBabelPlugin = require("./importMetaBabelPlugin");
 
 module.exports = babelJest.createTransformer({
   presets: [
     "babel-preset-react-app",
     "@babel/preset-react",
     "@babel/preset-typescript",
   ],
-  plugins: [
-    ["@babel/plugin-syntax-import-meta"],
-  ],
+  plugins: [[importMetaBabelPlugin]],
 });

packages/app-scripts-react/jest/importMetaBabelPlugin.js

@@ -0,0 +1,31 @@
+const template = require("@babel/template").default;
+
+const PUBLIC_ENV_REGEX = /^SNOWPACK_PUBLIC_/;
+function generateEnvObject(mode) {
+  const envObject = { ...process.env };
+  for (const env of Object.keys(envObject)) {
+    if (!PUBLIC_ENV_REGEX.test(env)) {
+      delete envObject[env];
+    }
+  }
+  envObject.MODE = mode;
+  envObject.NODE_ENV = mode;
+  return envObject;
+}
+
+/**
+ * Add import.meta.env support
+ * Note: import.meta.url is not supported at this time
+ */
+module.exports = function () {
+  const ast = template.ast(`
+  ({env: ${JSON.stringify(generateEnvObject("test"))}})
+`);
+  return {
+    visitor: {
+      MetaProperty(path, state) {
+        path.replaceWith(ast);
+      },
+    },
+  };
+};

packages/app-scripts-svelte/jest/babelTransform.js

@@ -8,6 +8,7 @@
 "use strict";
 
 const babelJest = require("babel-jest");
+const importMetaBabelPlugin = require("./importMetaBabelPlugin");
 
 module.exports = babelJest.createTransformer({
   presets: [
@@ -20,5 +21,5 @@ module.exports = babelJest.createTransformer({
       },
     ],
   ],
-  plugins: [],
+  plugins: [[importMetaBabelPlugin]],
 });

packages/app-scripts-svelte/jest/importMetaBabelPlugin.js

@@ -0,0 +1,31 @@
+const template = require("@babel/template").default;
+
+const PUBLIC_ENV_REGEX = /^SNOWPACK_PUBLIC_/;
+function generateEnvObject(mode) {
+  const envObject = { ...process.env };
+  for (const env of Object.keys(envObject)) {
+    if (!PUBLIC_ENV_REGEX.test(env)) {
+      delete envObject[env];
+    }
+  }
+  envObject.MODE = mode;
+  envObject.NODE_ENV = mode;
+  return envObject;
+}
+
+/**
+ * Add import.meta.env support
+ * Note: import.meta.url is not supported at this time
+ */
+module.exports = function () {
+  const ast = template.ast(`
+  ({env: ${JSON.stringify(generateEnvObject("test"))}})
+`);
+  return {
+    visitor: {
+      MetaProperty(path, state) {
+        path.replaceWith(ast);
+      },
+    },
+  };
+};