Add import.meta.env.* inlining support

- Add support for inlining import.meta.env.* patterns similar to process.env.*
- Support both --env=inline and --env=prefix* modes for import.meta.env
- Add comprehensive tests for import.meta.env inlining in bundler_env.test.ts
- Tests include inline mode, disable mode, prefix matching, and mixed usage
- Implementation creates import.meta.env defines by copying from process.env defines
- Framework defaults now support import.meta.env.* keys in addition to process.env.* keys

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/env_loader.zig

@@ -346,6 +346,9 @@ pub const Loader = struct {
             if (key.len > "process.env.".len and strings.eqlComptime(key[0.."process.env.".len], "process.env.")) {
                 const hashable_segment = key["process.env.".len..];
                 string_map_hashes[i] = bun.hash(hashable_segment);
+            } else if (key.len > "import.meta.env.".len and strings.eqlComptime(key[0.."import.meta.env.".len], "import.meta.env.")) {
+                const hashable_segment = key["import.meta.env.".len..];
+                string_map_hashes[i] = bun.hash(hashable_segment);
             }
         }
 
@@ -467,6 +470,23 @@ pub const Loader = struct {
             }
         }
 
+        // Create import.meta.env defines by copying from process.env defines
+        if (behavior != .disable and behavior != .load_all_without_inlining) {
+            var process_env_iter = to_string.iterator();
+            while (process_env_iter.next()) |entry| {
+                const process_key = entry.key_ptr.*;
+                
+                // Check if this is a process.env key
+                if (process_key.len > "process.env.".len and strings.eqlComptime(process_key[0.."process.env.".len], "process.env.")) {
+                    const var_name = process_key["process.env.".len..];
+                    const meta_key = try std.fmt.allocPrint(allocator, "import.meta.env.{s}", .{var_name});
+                    
+                    // Copy the define value
+                    _ = try to_string.getOrPutValue(meta_key, entry.value_ptr.*);
+                }
+            }
+        }
+
         for (framework_defaults.keys, 0..) |key, i| {
             const value = framework_defaults.values[i];
 

test/bundler/bundler_env.test.ts

@@ -116,5 +116,97 @@ for (let backend of ["api", "cli"] as const) {
           stdout: "process.env.BASE_URL\n$BASE_URL",
         },
       });
+    // import.meta.env tests
+    if (backend === "cli")
+      itBundled("import-meta-env/inline", {
+        env: {
+          VITE_FOO: "vite_bar",
+          VITE_BAZ: "vite_123",
+        },
+        backend: backend,
+        dotenv: "inline",
+        files: {
+          "/a.js": `
+        console.log(import.meta.env.VITE_FOO);
+        console.log(import.meta.env.VITE_BAZ);
+      `,
+        },
+        run: {
+          env: {
+            VITE_FOO: "vite_barz",
+            VITE_BAZ: "vite_123z",
+          },
+          stdout: "vite_bar\nvite_123\n",
+        },
+      });
+
+    itBundled("import-meta-env/disable", {
+      env: {
+        VITE_FOO: "vite_bar",
+        VITE_BAZ: "vite_123",
+      },
+      backend: backend,
+      dotenv: "disable",
+      files: {
+        "/a.js": `
+        console.log(import.meta.env.VITE_FOO);
+        console.log(import.meta.env.VITE_BAZ);
+      `,
+      },
+      run: {
+        stdout: "undefined\nundefined\n",
+      },
+    });
+
+    if (backend === "cli")
+      itBundled("import-meta-env/pattern-matching", {
+        env: {
+          VITE_PUBLIC_FOO: "vite_public_value",
+          VITE_PUBLIC_BAR: "vite_another_public",
+          VITE_PRIVATE_SECRET: "vite_secret_value",
+        },
+        dotenv: "VITE_PUBLIC_*",
+        backend: backend,
+        files: {
+          "/a.js": `
+        console.log(import.meta.env.VITE_PUBLIC_FOO);
+        console.log(import.meta.env.VITE_PUBLIC_BAR);
+        console.log(import.meta.env.VITE_PRIVATE_SECRET);
+      `,
+        },
+        run: {
+          env: {
+            VITE_PUBLIC_FOO: "VITE_BAD_FOO",
+            VITE_PUBLIC_BAR: "VITE_BAD_BAR",
+          },
+          stdout: "vite_public_value\nvite_another_public\nundefined\n",
+        },
+      });
+
+    // Test mixing process.env and import.meta.env
+    if (backend === "cli")
+      itBundled("mixed-env/inline", {
+        env: {
+          NODE_ENV: "production",
+          VITE_API_URL: "https://api.prod.com",
+        },
+        backend: backend,
+        dotenv: "inline",
+        files: {
+          "/a.js": `
+        console.log(process.env.NODE_ENV);
+        console.log(import.meta.env.VITE_API_URL);
+        console.log(import.meta.env.NODE_ENV);
+        console.log(process.env.VITE_API_URL);
+      `,
+        },
+        run: {
+          env: {
+            NODE_ENV: "development",
+            VITE_API_URL: "https://api.dev.com",
+          },
+          stdout: "production\nhttps://api.prod.com\nproduction\nhttps://api.prod.com\n",
+        },
+      });
   });
 }