fix(bug): fixes an issue with resolving .babelrc files when no explic…

…it path has been given. Closes #25

package.json

@@ -49,19 +49,19 @@
 	],
 	"license": "MIT",
 	"devDependencies": {
+		"@wessberg/rollup-plugin-ts": "^1.1.61",
 		"@wessberg/scaffold": "^1.0.19",
 		"@wessberg/ts-config": "^0.0.41",
-		"standard-changelog": "^2.0.11",
-		"@wessberg/rollup-plugin-ts": "^1.1.59",
-		"tslint": "^5.18.0",
-		"prettier": "^1.18.2",
-		"pretty-quick": "^1.11.1",
+		"ava": "2.2.0",
 		"husky": "^3.0.0",
 		"np": "^5.0.3",
+		"prettier": "^1.18.2",
+		"pretty-quick": "^1.11.1",
+		"rollup": "^1.17.0",
+		"standard-changelog": "^2.0.11",
 		"ts-node": "8.3.0",
-		"typescript": "^3.5.3",
-		"rollup": "^1.16.7",
-		"ava": "2.2.0"
+		"tslint": "^5.18.0",
+		"typescript": "^3.5.3"
 	},
 	"dependencies": {
 		"@babel/core": "^7.5.4",
@@ -75,11 +75,11 @@
 		"@babel/preset-env": "^7.5.4",
 		"@babel/runtime": "^7.5.4",
 		"@types/mkdirp": "^0.5.2",
-		"@types/node": "^12.6.1",
+		"@types/node": "^12.6.3",
 		"@types/resolve": "0.0.8",
 		"@wessberg/browserslist-generator": "1.0.23",
 		"@wessberg/stringutil": "^1.0.18",
-		"browserslist": "4.6.2",
+		"browserslist": "4.6.6",
 		"find-up": "^4.1.0",
 		"magic-string": "^0.25.3",
 		"mkdirp": "^0.5.1",

src/constant/constant.ts

@@ -16,6 +16,7 @@ export const SOURCE_MAP_COMMENT_REGEXP = /\n\/\/# sourceMappingURL=.*/g;
 export const TSLIB_NAME = `tslib${DECLARATION_EXTENSION}`;
 export const BABEL_RUNTIME_PREFIX_1 = "@babel/runtime/";
 export const BABEL_RUNTIME_PREFIX_2 = "babel-runtime/";
+export const BABEL_CONFIG_JS_FILENAME = "babel.config.js";
 
 export const REGENERATOR_RUNTIME_NAME_1 = `${BABEL_RUNTIME_PREFIX_1}regenerator/index.js`;
 export const REGENERATOR_RUNTIME_NAME_2 = `${BABEL_RUNTIME_PREFIX_2}regenerator/index.js`;

src/util/get-babel-config/find-babel-config-options.ts

@@ -0,0 +1,6 @@
+import {ITypescriptPluginBabelOptions} from "../../plugin/i-typescript-plugin-options";
+
+export interface FindBabelConfigOptions {
+	cwd: string;
+	babelConfig?: ITypescriptPluginBabelOptions["babelConfig"];
+}

src/util/get-babel-config/find-babel-config-result.ts

@@ -0,0 +1,22 @@
+import {IBabelInputOptions} from "../../plugin/i-babel-options";
+
+export interface FindBabelConfigResultBase {
+	kind: "project" | "relative" | "dict";
+}
+
+export interface FindBabelConfigDictResult extends FindBabelConfigResultBase {
+	kind: "dict";
+	options: Partial<IBabelInputOptions>;
+}
+
+export interface FindBabelConfigProjectResult extends FindBabelConfigResultBase {
+	kind: "project";
+	path: string;
+}
+
+export interface FindBabelConfigRelativeResult extends FindBabelConfigResultBase {
+	kind: "relative";
+	path: string;
+}
+
+export type FindBabelConfigResult = FindBabelConfigDictResult | FindBabelConfigProjectResult | FindBabelConfigRelativeResult;

src/util/get-babel-config/find-babel-config.ts

@@ -0,0 +1,81 @@
+import {BABEL_CONFIG_JS_FILENAME} from "../../constant/constant";
+import {join} from "path";
+import {FindBabelConfigOptions} from "./find-babel-config-options";
+import {ensureAbsolute} from "../path/path-util";
+import {FindBabelConfigResult} from "./find-babel-config-result";
+import {IBabelInputOptions} from "../../plugin/i-babel-options";
+// @ts-ignore
+import {findConfigUpwards, findRelativeConfig} from "@babel/core/lib/config/files/configuration";
+// @ts-ignore
+import {findPackageData} from "@babel/core/lib/config/files/package";
+
+/**
+ * Returns true if the given babelConfig is IBabelInputOptions
+ * @param {FindBabelConfigOptions["babelConfig"]} babelConfig
+ * @returns {babelConfig is IBabelInputOptions}
+ */
+export function isBabelInputOptions(babelConfig?: FindBabelConfigOptions["babelConfig"]): babelConfig is Partial<IBabelInputOptions> {
+	return babelConfig != null && typeof babelConfig !== "string";
+}
+
+/**
+ * Gets a Babel Config based on the given options
+ * @param {GetBabelConfigOptions} options
+ * @returns {GetBabelConfigResult}
+ */
+export function findBabelConfig({babelConfig, cwd}: FindBabelConfigOptions): FindBabelConfigResult | undefined {
+	// If babel options are provided directly
+	if (isBabelInputOptions(babelConfig)) {
+		return {
+			kind: "dict",
+			options: babelConfig
+		};
+	}
+
+	// If a config is given, determine its kind from its file name.
+	if (babelConfig != null) {
+		// This looks like a .babelrc or .babelrc.js file
+		if (babelConfig.startsWith(".babel")) {
+			return {
+				kind: "relative",
+				path: ensureAbsolute(cwd, babelConfig)
+			};
+		}
+
+		// This looks like a project-wide config (such as babel.config.js)
+		else {
+			return {
+				kind: "project",
+				path: ensureAbsolute(cwd, babelConfig)
+			};
+		}
+	}
+
+	// In all other cases, try to resolve a config. Prioritize project-wide configs such as 'babel.config.js'
+	// over relative ones such as '.babelrc'
+	const projectConfigPath = findConfigUpwards(cwd) as string | null;
+
+	// The resolved config will actually be the directory holding the config.
+	// If it is defined, join the default config name to it
+	if (projectConfigPath != null) {
+		return {
+			kind: "project",
+			// The resolved config will actually be the directory holding the config.
+			// If it is defined, join the default config name to it
+			path: join(projectConfigPath, BABEL_CONFIG_JS_FILENAME)
+		};
+	}
+
+	// If no config have been resolved, it might be possible to resolve a .babelrc or .babelrc.js file
+	const pkgData = findPackageData(join(cwd, "package.json"));
+	const relativeConfigResult = findRelativeConfig(pkgData, process.env.NODE_ENV) as {config: {filepath: string} | null} | null;
+	if (relativeConfigResult != null && relativeConfigResult.config != null) {
+		return {
+			kind: "relative",
+			path: relativeConfigResult.config.filepath
+		};
+	}
+
+	// No config could be resolved
+	return undefined;
+}

src/util/get-babel-config/i-get-babel-config-options.ts → src/util/get-babel-config/get-babel-config-options.ts

@@ -1,13 +1,11 @@
-import {ITypescriptPluginBabelOptions} from "../../plugin/i-typescript-plugin-options";
 import {IGetForcedBabelOptionsResult} from "../get-forced-babel-options/i-get-forced-babel-options-result";
 import {IGetDefaultBabelOptionsResult} from "../get-default-babel-options/i-get-default-babel-options-result";
 import {InputOptions} from "rollup";
+import {FindBabelConfigOptions} from "./find-babel-config-options";
 
-export interface IGetBabelConfigOptions {
-	cwd: string;
+export interface GetBabelConfigOptions extends FindBabelConfigOptions {
 	browserslist: string[] | undefined;
 	rollupInputOptions: InputOptions;
-	babelConfig?: ITypescriptPluginBabelOptions["babelConfig"];
 	forcedOptions?: IGetForcedBabelOptionsResult;
 	defaultOptions?: IGetDefaultBabelOptionsResult;
 }

src/util/get-babel-config/i-get-babel-config-result.ts → src/util/get-babel-config/get-babel-config-result.ts

@@ -1,6 +1,6 @@
 import {IBabelConfig} from "../../plugin/i-babel-options";
 
-export interface IGetBabelConfigResult {
+export interface GetBabelConfigResult {
 	config(filename: string): IBabelConfig;
 	minifyConfig: ((filename: string) => IBabelConfig) | undefined;
 	hasMinifyOptions: boolean;

src/util/get-babel-config/get-babel-config.ts

@@ -1,7 +1,5 @@
-import {IBabelConfigItem, IBabelInputOptions} from "../../plugin/i-babel-options";
-import {IGetBabelConfigOptions} from "./i-get-babel-config-options";
-import {ensureAbsolute, isBabelPluginTransformRuntime, isBabelPresetEnv, isYearlyBabelPreset} from "../path/path-util";
-import {IGetBabelConfigResult} from "./i-get-babel-config-result";
+import {IBabelConfigItem} from "../../plugin/i-babel-options";
+import {isBabelPluginTransformRuntime, isBabelPresetEnv, isYearlyBabelPreset} from "../path/path-util";
 import {
 	BABEL_MINIFICATION_BLACKLIST_PLUGIN_NAMES,
 	BABEL_MINIFICATION_BLACKLIST_PRESET_NAMES,
@@ -13,18 +11,12 @@ import {
 } from "../../constant/constant";
 // @ts-ignore
 import {createConfigItem, loadOptions, loadPartialConfig} from "@babel/core";
+import {GetBabelConfigOptions} from "./get-babel-config-options";
+import {GetBabelConfigResult} from "./get-babel-config-result";
+import {findBabelConfig} from "./find-babel-config";
 
 // tslint:disable:no-any
 
-/**
- * Returns true if the given babelConfig is IBabelInputOptions
- * @param {IGetBabelConfigOptions["babelConfig"]} babelConfig
- * @returns {babelConfig is IBabelInputOptions}
- */
-export function isBabelInputOptions(babelConfig?: IGetBabelConfigOptions["babelConfig"]): babelConfig is Partial<IBabelInputOptions> {
-	return babelConfig != null && typeof babelConfig !== "string";
-}
-
 /**
  * Combines the given two sets of presets
  * @param {IBabelConfigItem[]} userItems
@@ -101,8 +93,8 @@ function configItemIsAllowedDuringNoMinification({file: {resolved}}: IBabelConfi
 
 /**
  * Gets a Babel Config based on the given options
- * @param {IGetBabelConfigOptions} options
- * @returns {IGetBabelConfigResult}
+ * @param {GetBabelConfigOptions} options
+ * @returns {GetBabelConfigResult}
  */
 export function getBabelConfig({
 	babelConfig,
@@ -111,14 +103,20 @@ export function getBabelConfig({
 	defaultOptions = {},
 	browserslist,
 	rollupInputOptions
-}: IGetBabelConfigOptions): IGetBabelConfigResult {
+}: GetBabelConfigOptions): GetBabelConfigResult {
+	const resolvedConfig = findBabelConfig({cwd, babelConfig});
+
 	// Load a partial Babel config based on the input options
 	const partialConfig = loadPartialConfig(
-		isBabelInputOptions(babelConfig)
+		resolvedConfig != null && resolvedConfig.kind === "dict"
 			? // If the given babelConfig is an object of input options, use that as the basis for the full config
-			  {...babelConfig, cwd, root: cwd, configFile: false, babelrc: false}
+			  {...resolvedConfig.options, cwd, root: cwd, configFile: false, babelrc: false}
 			: // Load the path to a babel config provided to the plugin if any, otherwise try to resolve it
-			  {cwd, root: cwd, ...(babelConfig != null ? {configFile: ensureAbsolute(cwd, babelConfig)} : {})}
+			  {
+					cwd,
+					root: cwd,
+					...(resolvedConfig != null ? {configFile: resolvedConfig.path} : {babelrc: true})
+			  }
 	);
 
 	const {options, config} = partialConfig;