packages/babel-core/src/config/partial.js
// @flow
import path from "path";
import gensync, { type Handler } from "gensync";
import Plugin from "./plugin";
import { mergeOptions } from "./util";
import { createItemFromDescriptor } from "./item";
import { buildRootChain, type ConfigContext } from "./config-chain";
import { getEnv } from "./helpers/environment";
import {
validate,
type ValidatedOptions,
type RootMode,
} from "./validation/options";
import {
findConfigUpwards,
ROOT_CONFIG_FILENAMES,
type ConfigFile,
type IgnoreFile,
} from "./files";
function* resolveRootMode(
rootDir: string,
rootMode: RootMode,
): Handler<string> {
switch (rootMode) {
case "root":
return rootDir;
case "upward-optional": {
const upwardRootDir = yield* findConfigUpwards(rootDir);
return upwardRootDir === null ? rootDir : upwardRootDir;
}
case "upward": {
const upwardRootDir = yield* findConfigUpwards(rootDir);
if (upwardRootDir !== null) return upwardRootDir;
throw Object.assign(
(new Error(
`Babel was run with rootMode:"upward" but a root could not ` +
`be found when searching upward from "${rootDir}".\n` +
`One of the following config files must be in the directory tree: ` +
`"${ROOT_CONFIG_FILENAMES.join(", ")}".`,
): any),
{
code: "BABEL_ROOT_NOT_FOUND",
dirname: rootDir,
},
);
}
default:
throw new Error(`Assertion failure - unknown rootMode value.`);
}
}
type PrivPartialConfig = {
options: ValidatedOptions,
context: ConfigContext,
ignore: IgnoreFile | void,
babelrc: ConfigFile | void,
config: ConfigFile | void,
};
export default function* loadPrivatePartialConfig(
inputOpts: mixed,
): Handler<PrivPartialConfig | null> {
if (
inputOpts != null &&
(typeof inputOpts !== "object" || Array.isArray(inputOpts))
) {
throw new Error("Babel options must be an object, null, or undefined");
}
const args = inputOpts ? validate("arguments", inputOpts) : {};
const {
envName = getEnv(),
cwd = ".",
root: rootDir = ".",
rootMode = "root",
caller,
} = args;
const absoluteCwd = path.resolve(cwd);
const absoluteRootDir = yield* resolveRootMode(
path.resolve(absoluteCwd, rootDir),
rootMode,
);
const context: ConfigContext = {
filename:
typeof args.filename === "string"
? path.resolve(cwd, args.filename)
: undefined,
cwd: absoluteCwd,
root: absoluteRootDir,
envName,
caller,
};
const configChain = yield* buildRootChain(args, context);
if (!configChain) return null;
const options = {};
configChain.options.forEach(opts => {
mergeOptions(options, opts);
});
// Tack the passes onto the object itself so that, if this object is
// passed back to Babel a second time, it will be in the right structure
// to not change behavior.
options.babelrc = false;
options.configFile = false;
options.passPerPreset = false;
options.envName = context.envName;
options.cwd = context.cwd;
options.root = context.root;
options.filename =
typeof context.filename === "string" ? context.filename : undefined;
options.plugins = configChain.plugins.map(descriptor =>
createItemFromDescriptor(descriptor),
);
options.presets = configChain.presets.map(descriptor =>
createItemFromDescriptor(descriptor),
);
return {
options,
context,
ignore: configChain.ignore,
babelrc: configChain.babelrc,
config: configChain.config,
};
}
export const loadPartialConfig = gensync<[any], PartialConfig | null>(
function* (inputOpts: mixed): Handler<PartialConfig | null> {
const result: ?PrivPartialConfig = yield* loadPrivatePartialConfig(
inputOpts,
);
if (!result) return null;
const { options, babelrc, ignore, config } = result;
(options.plugins || []).forEach(item => {
if (item.value instanceof Plugin) {
throw new Error(
"Passing cached plugin instances is not supported in " +
"babel.loadPartialConfig()",
);
}
});
return new PartialConfig(
options,
babelrc ? babelrc.filepath : undefined,
ignore ? ignore.filepath : undefined,
config ? config.filepath : undefined,
);
},
);
export type { PartialConfig };
class PartialConfig {
/**
* These properties are public, so any changes to them should be considered
* a breaking change to Babel's API.
*/
options: ValidatedOptions;
babelrc: string | void;
babelignore: string | void;
config: string | void;
constructor(
options: ValidatedOptions,
babelrc: string | void,
ignore: string | void,
config: string | void,
) {
this.options = options;
this.babelignore = ignore;
this.babelrc = babelrc;
this.config = config;
// Freeze since this is a public API and it should be extremely obvious that
// reassigning properties on here does nothing.
Object.freeze(this);
}
/**
* Returns true if there is a config file in the filesystem for this config.
*/
hasFilesystemConfig(): boolean {
return this.babelrc !== undefined || this.config !== undefined;
}
}
Object.freeze(PartialConfig.prototype);