fix: support BROWSERSLIST{,_CONFIG} env (babel#16907)

nicolo-ribaudo · Oct 17, 2024 · d658738 · d658738
1 parent 33d705e
commit d658738
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Showing 3 changed files with 60 additions and 17 deletions.
diff --git a/packages/babel-helper-compilation-targets/src/index.ts b/packages/babel-helper-compilation-targets/src/index.ts
@@ -215,14 +215,20 @@ export default function getTargets(
     !options.ignoreBrowserslistConfig && !hasTargets;
 
   if (!browsers && shouldSearchForConfig) {
-    const configFile =
-      options.configFile ?? browserslist.findConfigFile(configPath);
-    if (configFile != null) {
-      onBrowserslistConfigFound?.(configFile);
-      browsers = browserslist.loadConfig({
-        config: configFile,
-        env: options.browserslistEnv,
-      });
+    // https://github.com/browserslist/browserslist/blob/8ae85caa905d130f4ca86f7a998a5b63abbbe582/node.js#L243
+    browsers = process.env.BROWSERSLIST;
+    if (!browsers) {
+      const configFile =
+        options.configFile ||
+        process.env.BROWSERSLIST_CONFIG ||
+        browserslist.findConfigFile(configPath);
+      if (configFile != null) {
+        onBrowserslistConfigFound?.(configFile);
+        browsers = browserslist.loadConfig({
+          config: configFile,
+          env: options.browserslistEnv,
+        });
+      }
     }
 
     if (browsers == null) {

diff --git a/packages/babel-helper-compilation-targets/test/targets-parser.spec.js b/packages/babel-helper-compilation-targets/test/targets-parser.spec.js
@@ -1,10 +1,8 @@
 import browserslist from "browserslist";
-import { join, dirname } from "path";
-import { fileURLToPath } from "url";
-
 import _getTargets from "../lib/index.js";
 const getTargets = _getTargets.default || _getTargets;
-import { itBabel8, itBabel7 } from "$repo-utils";
+import { itBabel8, itBabel7, commonJS } from "$repo-utils";
+const { require } = commonJS(import.meta.url);
 
 describe("getTargets", () => {
   it("parses", () => {
@@ -63,6 +61,28 @@ describe("getTargets", () => {
     expect(parseFloat(actual.chrome)).toBeGreaterThan(4);
   });
 
+  describe("when process.env.BROWSERSLIST is specified", () => {
+    afterAll(() => {
+      delete process.env.BROWSERSLIST;
+    });
+    it("should provide fallback to any targets option", () => {
+      process.env.BROWSERSLIST = "firefox 2";
+      expect(getTargets()).toEqual({ firefox: "2.0.0" });
+    });
+  });
+
+  describe("when process.env.BROWSERSLIST_CONFIG is specified", () => {
+    afterAll(() => {
+      delete process.env.BROWSERSLIST_CONFIG;
+    });
+    it("should provide fallback to any targets option", () => {
+      process.env.BROWSERSLIST_CONFIG = require.resolve(
+        "./fixtures/.browserslistrc",
+      );
+      expect(getTargets()).toEqual({ firefox: "30.0.0", chrome: "70.0.0" });
+    });
+  });
+
   describe("validation", () => {
     it("throws on invalid target name", () => {
       const invalidTargetName = () => {
@@ -264,11 +284,7 @@ describe("getTargets", () => {
             esmodules: "intersect",
           },
           {
-            configPath: join(
-              dirname(fileURLToPath(import.meta.url)),
-              "fixtures",
-              "foo.js",
-            ),
+            configPath: require.resolve("./fixtures/.browserslistrc"),
           },
         ),
       ).toMatchSnapshot();

diff --git a/packages/babel-preset-env/test/index.skip-bundled.js b/packages/babel-preset-env/test/index.skip-bundled.js
@@ -389,4 +389,25 @@ describe("babel-preset-env", () => {
   it.todo(
     "should add .browserslistrc to external dependencies when browserslistConfigFile is specified",
   );
+
+  describe("when process.env.BROWSERSLIST_CONFIG is specified", () => {
+    afterEach(() => {
+      delete process.env.BROWSERSLIST_CONFIG;
+    });
+    it("should add process.env.BROWSERSLIST_CONFIG to external dependencies using preset-env's resolveTarget", () => {
+      const browserslistConfigFile = require.resolve(
+        "./regressions/.browserslistrc",
+      );
+      process.env.BROWSERSLIST_CONFIG = browserslistConfigFile;
+      const { externalDependencies } = babel.transformSync("", {
+        configFile: false,
+        presets: [[babelPresetEnv.default, { browserslistEnv: "development" }]],
+      });
+      expect(externalDependencies).toContain(browserslistConfigFile);
+    });
+
+    it.todo(
+      "should add process.env.BROWSERSLIST_CONFIG to external dependencies using core's resolveTarget",
+    );
+  });
 });