eslint-config-webpack/configs/utils/is-typescript-installed.js

Provides Webpack's eslint rules as an extensible shared config

import getJsonFile from "./get-json-file.js";

/**
 * @returns {boolean} true when typescript is supported by project, otherwise false
 */
function isTypescriptInstalled() {
	/** @type {import("type-fest").PackageJson | null} */
	const packageJson = getJsonFile("package.json");

	if (packageJson === null) {
		return false;
	}

	const dependencies = packageJson.dependencies || {};
	const devDependencies = packageJson.devDependencies || {};

	return Boolean(
		typeof dependencies.typescript !== "undefined" ||
		typeof devDependencies.typescript !== "undefined",
	);
}

export default isTypescriptInstalled;