Merge .babelrc and .babelignore searching into a single pass.

packages/babel-core/src/config/config-chain.js

@@ -12,12 +12,7 @@ import {
 
 const debug = buildDebug("babel:config:config-chain");
 
-import {
-  findBabelrc,
-  findBabelignore,
-  loadConfig,
-  type ConfigFile,
-} from "./files";
+import { findRelativeConfig, loadConfig, type ConfigFile } from "./files";
 
 import { makeWeakCache, makeStrongCache } from "./caching";
 
@@ -124,22 +119,15 @@ export function buildRootChain(
   // resolve all .babelrc files
   if (opts.babelrc !== false && context.filename !== null) {
     const filename = context.filename;
-    const babelignoreFile = findBabelignore(filename);
-    if (
-      babelignoreFile &&
-      shouldIgnore(
-        context,
-        babelignoreFile.ignore,
-        null,
-        babelignoreFile.dirname,
-      )
-    ) {
+
+    const { ignore, config } = findRelativeConfig(filename, context.envName);
+
+    if (ignore && shouldIgnore(context, ignore.ignore, null, ignore.dirname)) {
       return null;
     }
 
-    const babelrcFile = findBabelrc(filename, context.envName);
-    if (babelrcFile) {
-      const result = loadFileChain(babelrcFile, context);
+    if (config) {
+      const result = loadFileChain(config, context);
       if (!result) return null;
 
       mergeChain(fileChain, result);

packages/babel-core/src/config/files/configuration.js

@@ -21,41 +21,58 @@ export type IgnoreFile = {
   ignore: Array<string>,
 };
 
+export type RelativeConfig = {
+  config: ConfigFile | null,
+  ignore: IgnoreFile | null,
+};
+
 const BABELRC_FILENAME = ".babelrc";
 const BABELRC_JS_FILENAME = ".babelrc.js";
 const PACKAGE_FILENAME = "package.json";
 const BABELIGNORE_FILENAME = ".babelignore";
 
-export function findBabelrc(
+export function findRelativeConfig(
   filepath: string,
   envName: string,
-): ConfigFile | null {
+): RelativeConfig {
+  let config = null;
+  let ignore = null;
+
   const dirname = path.dirname(filepath);
   let loc = dirname;
   while (true) {
-    const conf = [
-      BABELRC_FILENAME,
-      BABELRC_JS_FILENAME,
-      PACKAGE_FILENAME,
-    ].reduce((previousConfig: ConfigFile | null, name) => {
-      const filepath = path.join(loc, name);
-      const config = readConfig(filepath, envName);
+    if (!config) {
+      config = [BABELRC_FILENAME, BABELRC_JS_FILENAME, PACKAGE_FILENAME].reduce(
+        (previousConfig: ConfigFile | null, name) => {
+          const filepath = path.join(loc, name);
+          const config = readConfig(filepath, envName);
 
-      if (config && previousConfig) {
-        throw new Error(
-          `Multiple configuration files found. Please remove one:\n` +
-            ` - ${path.basename(previousConfig.filepath)}\n` +
-            ` - ${name}\n` +
-            `from ${loc}`,
-        );
+          if (config && previousConfig) {
+            throw new Error(
+              `Multiple configuration files found. Please remove one:\n` +
+                ` - ${path.basename(previousConfig.filepath)}\n` +
+                ` - ${name}\n` +
+                `from ${loc}`,
+            );
+          }
+
+          return config || previousConfig;
+        },
+        null,
+      );
+
+      if (config) {
+        debug("Found configuration %o from %o.", config.filepath, dirname);
       }
+    }
 
-      return config || previousConfig;
-    }, null);
+    if (!ignore) {
+      const ignoreLoc = path.join(loc, BABELIGNORE_FILENAME);
+      ignore = readIgnoreConfig(ignoreLoc);
 
-    if (conf) {
-      debug("Found configuration %o from %o.", conf.filepath, dirname);
-      return conf;
+      if (ignore) {
+        debug("Found ignore %o from %o.", ignore.filepath, dirname);
+      }
     }
 
     const nextLoc = path.dirname(loc);
@@ -63,27 +80,7 @@ export function findBabelrc(
     loc = nextLoc;
   }
 
-  return null;
-}
-
-export function findBabelignore(filepath: string): IgnoreFile | null {
-  const dirname = path.dirname(filepath);
-  let loc = dirname;
-  while (true) {
-    const ignoreLoc = path.join(loc, BABELIGNORE_FILENAME);
-    const ignore = readIgnoreConfig(ignoreLoc);
-
-    if (ignore) {
-      debug("Found ignore %o from %o.", ignore.filepath, dirname);
-      return ignore;
-    }
-
-    const nextLoc = path.dirname(loc);
-    if (loc === nextLoc) break;
-    loc = nextLoc;
-  }
-
-  return null;
+  return { config, ignore };
 }
 
 export function loadConfig(
@@ -106,7 +103,7 @@ export function loadConfig(
  * Read the given config file, returning the result. Returns null if no config was found, but will
  * throw if there are parsing errors while loading a config.
  */
-function readConfig(filepath, envName) {
+function readConfig(filepath, envName): ConfigFile | null {
   return path.extname(filepath) === ".js"
     ? readConfigJS(filepath, { envName })
     : readConfigFile(filepath);

packages/babel-core/src/config/files/index-browser.js

@@ -12,16 +12,16 @@ export type IgnoreFile = {
   ignore: Array<string>,
 };
 
-export function findBabelrc(
+export type RelativeConfig = {
+  config: ConfigFile | null,
+  ignore: IgnoreFile | null,
+};
+
+export function findRelativeConfig(
   filepath: string,
   envName: string, // eslint-disable-line no-unused-vars
-): ConfigFile | null {
-  return null;
-}
-
-// eslint-disable-next-line no-unused-vars
-export function findBabelignore(filepath: string): IgnoreFile | null {
-  return null;
+): RelativeConfig {
+  return { config: null, ignore: null };
 }
 
 export function loadConfig(name: string, dirname: string): ConfigFile {