eslint-plugin-unicorn/rules/prefer-string-raw.js

More than 100 powerful ESLint rules

import {isStringLiteral, isDirective} from './ast/index.js';
import {fixSpaceAroundKeyword} from './fix/index.js';

const MESSAGE_ID = 'prefer-string-raw';
const messages = {
	[MESSAGE_ID]: '`String.raw` should be used to avoid escaping `\\`.',
};

const BACKSLASH = '\\';

function unescapeBackslash(raw) {
	const quote = raw.charAt(0);

	raw = raw.slice(1, -1);

	let result = '';
	for (let position = 0; position < raw.length; position++) {
		const character = raw[position];
		if (character === BACKSLASH) {
			const nextCharacter = raw[position + 1];
			if (nextCharacter === BACKSLASH || nextCharacter === quote) {
				result += nextCharacter;
				position++;
				continue;
			}
		}

		result += character;
	}

	return result;
}

/** @param {import('eslint').Rule.RuleContext} context */
const create = context => {
	context.on('Literal', node => {
		if (
			!isStringLiteral(node)
			|| isDirective(node.parent)
			|| (
				(
					node.parent.type === 'ImportDeclaration'
					|| node.parent.type === 'ExportNamedDeclaration'
					|| node.parent.type === 'ExportAllDeclaration'
				) && node.parent.source === node
			)
			|| (node.parent.type === 'Property' && !node.parent.computed && node.parent.key === node)
			|| (node.parent.type === 'JSXAttribute' && node.parent.value === node)
			|| (node.parent.type === 'TSEnumMember' && (node.parent.initializer === node || node.parent.id === node))
			|| (node.parent.type === 'ImportAttribute' && (node.parent.key === node || node.parent.value === node))
		) {
			return;
		}

		const {sourceCode} = context;
		const {raw} = node;
		if (
			raw.at(-2) === BACKSLASH
			|| !raw.includes(BACKSLASH + BACKSLASH)
			|| raw.includes('`')
			|| raw.includes('${')
			|| sourceCode.getLoc(node).start.line !== sourceCode.getLoc(node).end.line
		) {
			return;
		}

		const unescaped = unescapeBackslash(raw);
		if (unescaped !== node.value) {
			return;
		}

		return {
			node,
			messageId: MESSAGE_ID,
			* fix(fixer) {
				yield fixer.replaceText(node, `String.raw\`${unescaped}\``);
				yield * fixSpaceAroundKeyword(fixer, node, sourceCode);
			},
		};
	});
};

/** @type {import('eslint').Rule.RuleModule} */
const config = {
	create,
	meta: {
		type: 'suggestion',
		docs: {
			description: 'Prefer using the `String.raw` tag to avoid escaping `\\`.',
			recommended: true,
		},
		fixable: 'code',
		messages,
	},
};

export default config;