50.js

const fs = require("fs");
const path = require("path");
const arrify = require("arrify");
const which = require("which");
const readPkgUp = require("read-pkg-up");

const hasOwn = (obj, key) =>
	obj.hasOwnProperty(key) && obj[key] !== null && obj[key] !== undefined;

const hasPath = (obj, keys) => {
	const [key, ...tail] = keys;
	if (hasOwn(obj, key)) {
		if (tail && tail.length) {
			return hasPath(obj[key], tail);
		} else {
			return true;
		}
	} else {
		return false;
	}
};

const has = (obj, keypath) => hasPath(obj, keypath.split(/[./]/));

const { pkg, path: pkgPath } = readPkgUp.sync({
	cwd: fs.realpathSync(process.cwd()),
});

const appDirectory = path.dirname(pkgPath);

const fromRoot = (...p) => path.join(appDirectory, ...p);
const hasFile = (...p) => fs.existsSync(fromRoot(...p));

const hasPkgProp = props => arrify(props).some(prop => has(pkg, prop));

const hasPkgSubProp = pkgProp => props =>
	hasPkgProp(arrify(props).map(p => `${pkgProp}.${p}`));

const hasPeerDep = hasPkgSubProp("peerDependencies");
const hasDep = hasPkgSubProp("dependencies");
const hasDevDep = hasPkgSubProp("devDependencies");
const hasAnyDep = args => [hasDep, hasDevDep, hasPeerDep].some(fn => fn(args));

const ifAnyDep = (deps, t, f) => (hasAnyDep(arrify(deps)) ? t : f);

function parseEnv(name, def) {
	if (envIsSet(name)) {
		try {
			return JSON.parse(process.env[name] || "<fail>");
		} catch (err) {
			return process.env[name];
		}
	}
	return def;
}

function envIsSet(name) {
	return (
		process.env.hasOwnProperty(name) &&
		process.env[name] &&
		process.env[name] !== "undefined"
	);
}

function resolveBin(
	modName,
	{ executable = modName, cwd = process.cwd() } = {},
) {
	let pathFromWhich;
	try {
		pathFromWhich = fs.realpathSync(which.sync(executable));
	} catch (_error) {
		// ignore _error
	}
	try {
		const modPkgPath = require.resolve(`${modName}/package.json`);
		const modPkgDir = path.dirname(modPkgPath);
		const { bin } = require(modPkgPath);
		const binPath = typeof bin === "string" ? bin : bin[executable];
		const fullPathToBin = path.join(modPkgDir, binPath);
		if (fullPathToBin === pathFromWhich) {
			return executable;
		}
		return fullPathToBin.replace(cwd, ".");
	} catch (error) {
		if (pathFromWhich) {
			return executable;
		}
		throw error;
	}
}

module.exports = {
	fromRoot,
	hasFile,
	hasPkgProp,
	ifAnyDep,
	parseEnv,
	resolveBin,
};