Expose a 'cwd' option for Babel's root options.

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

@@ -39,16 +39,17 @@ type ConfigPart =
     };
 
 export default function buildConfigChain(
+  cwd: string,
   opts: ValidatedOptions,
   envName: string,
 ): Array<ConfigItem> | null {
-  const filename = opts.filename ? path.resolve(opts.filename) : null;
+  const filename = opts.filename ? path.resolve(cwd, opts.filename) : null;
   const builder = new ConfigChainBuilder(
     filename ? new LoadedFile(filename) : null,
   );
 
   try {
-    builder.mergeConfigArguments(opts, process.cwd(), envName);
+    builder.mergeConfigArguments(opts, cwd, envName);
 
     // resolve all .babelrc files
     if (opts.babelrc !== false && filename) {

packages/babel-core/src/config/option-manager.js

@@ -1,5 +1,6 @@
 // @flow
 
+import path from "path";
 import * as context from "../index";
 import Plugin, { validatePluginObject } from "./plugin";
 import merge from "lodash/merge";
@@ -103,9 +104,10 @@ class OptionManager {
   init(inputOpts: {}) {
     const args = validate("arguments", inputOpts);
 
-    const { envName = getEnv() } = args;
+    const { envName = getEnv(), cwd = "." } = args;
+    const absoluteCwd = path.resolve(cwd);
 
-    const configChain = buildConfigChain(args, envName);
+    const configChain = buildConfigChain(absoluteCwd, args, envName);
     if (!configChain) return null;
 
     try {
@@ -134,6 +136,7 @@ class OptionManager {
       .map(plugins => ({ plugins }));
     opts.passPerPreset = opts.presets.length > 0;
     opts.envName = envName;
+    opts.cwd = absoluteCwd;
 
     return {
       options: opts,

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

@@ -17,6 +17,7 @@ import {
 } from "./option-assertions";
 
 const ROOT_VALIDATORS: ValidatorSet = {
+  cwd: (assertString: Validator<$PropertyType<ValidatedOptions, "cwd">>),
   filename: (assertString: Validator<
     $PropertyType<ValidatedOptions, "filename">,
   >),
@@ -128,6 +129,7 @@ const COMMON_VALIDATORS: ValidatorSet = {
 export type InputOptions = ValidatedOptions;
 
 export type ValidatedOptions = {
+  cwd?: string,
   filename?: string,
   filenameRelative?: string,
   babelrc?: boolean,

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

@@ -1,10 +1,14 @@
 import assert from "assert";
 import fs from "fs";
 import path from "path";
-import buildConfigChain from "../lib/config/build-config-chain";
+import buildConfigChainFn from "../lib/config/build-config-chain";
 
 const DEFAULT_ENV = "development";
 
+function buildConfigChain(opts, envName) {
+  return buildConfigChainFn(process.cwd(), opts, envName);
+}
+
 function fixture() {
   const args = [__dirname, "fixtures", "config"];
   for (let i = 0; i < arguments.length; i++) {