routie dev init since i didn't adhere to any proper guidance up until now

frontend/node_modules/eslint-plugin-unicorn/rules/escape-case.js

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+import {replaceTemplateElement} from './fix/index.js';
+import {isRegexLiteral, isStringLiteral, isTaggedTemplateLiteral} from './ast/index.js';
+
+const MESSAGE_ID_UPPERCASE = 'escape-uppercase';
+const MESSAGE_ID_LOWERCASE = 'escape-lowercase';
+const messages = {
+	[MESSAGE_ID_UPPERCASE]: 'Use uppercase characters for the value of the escape sequence.',
+	[MESSAGE_ID_LOWERCASE]: 'Use lowercase characters for the value of the escape sequence.',
+};
+
+const escapeCase = /(?<=(?:^|[^\\])(?:\\\\)*\\)(?<data>x[\dA-Fa-f]{2}|u[\dA-Fa-f]{4}|u{[\dA-Fa-f]+})/g;
+const escapePatternCase = /(?<=(?:^|[^\\])(?:\\\\)*\\)(?<data>x[\dA-Fa-f]{2}|u[\dA-Fa-f]{4}|u{[\dA-Fa-f]+}|c[A-Za-z])/g;
+const getProblem = ({node, original, regex = escapeCase, lowercase, fix}) => {
+	const fixed = original.replace(regex, data => data[0] + data.slice(1)[lowercase ? 'toLowerCase' : 'toUpperCase']());
+
+	if (fixed !== original) {
+		return {
+			node,
+			messageId: lowercase ? MESSAGE_ID_LOWERCASE : MESSAGE_ID_UPPERCASE,
+			fix: fixer => fix ? fix(fixer, fixed) : fixer.replaceText(node, fixed),
+		};
+	}
+};
+
+/** @param {import('eslint').Rule.RuleContext} context */
+const create = context => {
+	const lowercase = context.options[0] === 'lowercase';
+
+	context.on('Literal', node => {
+		if (isStringLiteral(node)) {
+			return getProblem({
+				node,
+				original: node.raw,
+				lowercase,
+			});
+		}
+	});
+
+	context.on('Literal', node => {
+		if (isRegexLiteral(node)) {
+			return getProblem({
+				node,
+				original: node.raw,
+				regex: escapePatternCase,
+				lowercase,
+			});
+		}
+	});
+
+	context.on('TemplateElement', node => {
+		if (isTaggedTemplateLiteral(node.parent, ['String.raw'])) {
+			return;
+		}
+
+		return getProblem({
+			node,
+			original: node.value.raw,
+			lowercase,
+			fix: (fixer, fixed) => replaceTemplateElement(node, fixed, context, fixer),
+		});
+	});
+};
+
+const schema = [
+	{
+		enum: ['uppercase', 'lowercase'],
+		description: 'The case style for escape sequences.',
+	},
+];
+
+/** @type {import('eslint').Rule.RuleModule} */
+const config = {
+	create,
+	meta: {
+		type: 'suggestion',
+		docs: {
+			description: 'Require escape sequences to use uppercase or lowercase values.',
+			recommended: 'unopinionated',
+		},
+		fixable: 'code',
+		schema,
+		defaultOptions: ['uppercase'],
+		messages,
+	},
+};
+
+export default config;