eslint-plugin-unused-imports/lib/rules/predicates.js

Report and remove unused es6 modules

exports.unusedVarsPredicate = (problem, context) => {
	const { node } = problem;
	const { parent } = node;

	// If parent is null just let the composed rule handle it
	if (parent == null) {
		return problem;
	}

	// Remove these 3 cases, pass any other trough.
	switch (parent.type) {
		case "ImportSpecifier":
		case "ImportDefaultSpecifier":
		case "ImportNamespaceSpecifier":
			return false;
		default:
			return problem;
	}
};

const commaFilter = { filter: (token) => token.value === "," };
const includeCommentsFilter = { includeComments: true };

exports.unusedImportsPredicate = (problem, context) => {
	const { sourceCode } = context;

	const { node } = problem;
	const { parent } = node;

	// If parent is null just let the composed rule handle it
	if (parent == null) {
		return problem;
	}

	// Only handle these 3 cases.
	switch (parent.type) {
		case "ImportSpecifier":
		case "ImportDefaultSpecifier":
		case "ImportNamespaceSpecifier":
			break;
		default:
			return false;
	}

	problem.fix = (fixer) => {
		if (!parent) {
			return null;
		}
		const grandParent = parent.parent;

		if (!grandParent) {
			return null;
		}

		// Only one import
		if (grandParent.specifiers.length === 1) {
			const nextToken = sourceCode.getTokenAfter(grandParent, includeCommentsFilter);
			const newLinesBetween = nextToken ? nextToken.loc.start.line - grandParent.loc.start.line : 0;
			const endOfReplaceRange = nextToken ? nextToken.range[0] : grandParent.range[1]
			const count = Math.max(0, newLinesBetween - 1);

			return [
				fixer.remove(grandParent),
				fixer.replaceTextRange([grandParent.range[1], endOfReplaceRange], "\n".repeat(count)),
			];
		}

		// Not last specifier
		if (parent !== grandParent.specifiers[grandParent.specifiers.length - 1]) {
			const comma = sourceCode.getTokenAfter(parent, commaFilter);
			const prevNode = sourceCode.getTokenBefore(parent);

			return [
				fixer.removeRange([prevNode.range[1], parent.range[0]]),
				fixer.remove(parent),
				fixer.remove(comma),
			];
		}

		// Default export and a single normal left, ex. "import default, { package1 } from 'module';"
		if (
			grandParent.specifiers.filter((specifier) => specifier.type === "ImportSpecifier").length ===
			1
		) {
			const start = sourceCode.getTokenBefore(parent, commaFilter);
			const end = sourceCode.getTokenAfter(parent, { filter: (token) => token.value === "}" });

			return fixer.removeRange([start.range[0], end.range[1]]);
		}

		return fixer.removeRange([
			sourceCode.getTokenBefore(parent, commaFilter).range[0],
			parent.range[1],
		]);
	};
	return problem;
};