eslint-config-webpack/plugins/webpack/rules/require-license-comment.js

Provides Webpack's eslint rules as an extensible shared config

/** @typedef {import("estree").Comment} Comment */
/** @typedef {import("eslint").AST.SourceLocation} SourceLocation */

/**
 * @type {import("eslint").Rule.RuleModule} rule rule
 */
export const rule = {
	create(context) {
		const sourceCode = context.getSourceCode();

		return {
			"Program:exit"(program) {
				const comments = sourceCode.getAllComments();
				const licenseComment =
					/** @type {(Comment & { start: number, end: number }) | undefined} */
					(
						comments.find(
							(comment) =>
								comment.type === "Block" &&
								/\n\s*MIT License http:\/\/www\.opensource\.org\/licenses\/mit-license\.php\n\s*(?:(Authors? .+)\n)?\s*/g.test(
									comment.value,
								),
						)
					);

				if (!licenseComment) {
					context.report({
						loc: program.loc,
						message: "Expected license comment.",
					});

					return;
				}

				const afterComment = sourceCode.text[licenseComment.end];

				if (afterComment !== "\n") {
					context.report({
						loc: /** @type {SourceLocation} */ (licenseComment.loc),
						message: "Expected newline after license comment.",
					});

					return;
				}

				const afterAfterComment = sourceCode.text[licenseComment.end + 1];

				if (afterAfterComment !== "\n") {
					context.report({
						loc: /** @type {SourceLocation} */ (licenseComment.loc),
						message: "Expected newline after license comment.",
					});
				}
			},
		};
	},
	meta: {
		docs: {
			category: "Best Practices",
			description: "Require license comment",
			recommended: true,
		},
		fixable: "code",
		type: "layout",
	},
};