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

frontend/node_modules/eslint-plugin-unicorn/rules/no-invalid-fetch-options.js

@@ -0,0 +1,112 @@
+import {getStaticValue} from '@eslint-community/eslint-utils';
+import {
+	isCallExpression,
+	isNewExpression,
+	isUndefined,
+	isNullLiteral,
+} from './ast/index.js';
+
+const MESSAGE_ID_ERROR = 'no-invalid-fetch-options';
+const messages = {
+	[MESSAGE_ID_ERROR]: '"body" is not allowed when method is "{{method}}".',
+};
+
+const isObjectPropertyWithName = (node, name) =>
+	node.type === 'Property'
+	&& !node.computed
+	&& node.key.type === 'Identifier'
+	&& node.key.name === name;
+
+function checkFetchOptions(context, node) {
+	if (node.type !== 'ObjectExpression') {
+		return;
+	}
+
+	const {properties} = node;
+
+	const bodyProperty = properties.findLast(property => isObjectPropertyWithName(property, 'body'));
+
+	if (!bodyProperty) {
+		return;
+	}
+
+	const bodyValue = bodyProperty.value;
+	if (isUndefined(bodyValue) || isNullLiteral(bodyValue)) {
+		return;
+	}
+
+	const methodProperty = properties.findLast(property => isObjectPropertyWithName(property, 'method'));
+	// If `method` is omitted but there is a `SpreadElement`, we just ignore the case
+	if (!methodProperty) {
+		if (properties.some(node => node.type === 'SpreadElement')) {
+			return;
+		}
+
+		return {
+			node: bodyProperty.key,
+			messageId: MESSAGE_ID_ERROR,
+			data: {method: 'GET'},
+		};
+	}
+
+	const methodValue = methodProperty.value;
+
+	const scope = context.sourceCode.getScope(methodValue);
+	let method = getStaticValue(methodValue, scope)?.value;
+
+	if (typeof method !== 'string') {
+		return;
+	}
+
+	method = method.toUpperCase();
+	if (method !== 'GET' && method !== 'HEAD') {
+		return;
+	}
+
+	return {
+		node: bodyProperty.key,
+		messageId: MESSAGE_ID_ERROR,
+		data: {method},
+	};
+}
+
+/** @param {import('eslint').Rule.RuleContext} context */
+const create = context => {
+	context.on('CallExpression', callExpression => {
+		if (!isCallExpression(callExpression, {
+			name: 'fetch',
+			minimumArguments: 2,
+			optional: false,
+		})) {
+			return;
+		}
+
+		return checkFetchOptions(context, callExpression.arguments[1]);
+	});
+
+	context.on('NewExpression', newExpression => {
+		if (!isNewExpression(newExpression, {
+			name: 'Request',
+			minimumArguments: 2,
+		})) {
+			return;
+		}
+
+		return checkFetchOptions(context, newExpression.arguments[1]);
+	});
+};
+
+/** @type {import('eslint').Rule.RuleModule} */
+const config = {
+	create,
+	meta: {
+		type: 'problem',
+		docs: {
+			description: 'Disallow invalid options in `fetch()` and `new Request()`.',
+			recommended: 'unopinionated',
+		},
+		messages,
+	},
+};
+
+export default config;