chore: switch from biome to eslint + prettier; fix ton of lint issues

1 files changed, 107 insertions, 0 deletions

diff --git a/eslint/rules/prefer-object-params.mjs b/eslint/rules/prefer-object-params.mjs
new file mode 100644
index 00000000..a5a8caae
--- /dev/null
+++ b/eslint/rules/prefer-object-params.mjs
@@ -0,0 +1,107 @@
+export default {
+	meta: {
+		type: "suggestion",
+		docs: {
+			description:
+				"Prefer a single destructured object parameter over multiple positional parameters",
+		},
+		schema: [],
+		messages: {
+			preferObjectParams:
+				"Use a single destructured object parameter instead of multiple positional parameters. Example: function someFunction({ name, age }: { name: string, age: number }) {}",
+		},
+	},
+	create(context) {
+		function isCallArgument(node) {
+			return (
+				node &&
+				(node.type === "CallExpression" ||
+					node.type === "NewExpression" ||
+					node.type === "OptionalCallExpression")
+			);
+		}
+
+		function isDirectCallback(node) {
+			const parent = node.parent;
+			return (
+				isCallArgument(parent) && parent.arguments.includes(node)
+			);
+		}
+
+		// Some APIs receive callbacks via a property somewhere inside an inline
+		// option object (e.g. `persist(state, { migrate: (s, v) => ... })` or
+		// `betterAuth({ rateLimit: { customStorage: { set: (k, v) => ... }}})`).
+		// The caller still dictates the signature, so the same carve-out as
+		// `isDirectCallback` applies. Pre-declared option objects don't qualify —
+		// once you name the object, the signature is yours to evolve.
+		function isInlineOptionCallback(node) {
+			let current = node;
+			let property = current.parent;
+			if (
+				!property ||
+				property.type !== "Property" ||
+				property.value !== current
+			) {
+				return false;
+			}
+
+			let objectExpression = property.parent;
+			while (objectExpression?.type === "ObjectExpression") {
+				const parent = objectExpression.parent;
+				if (isCallArgument(parent) && parent.arguments.includes(objectExpression)) {
+					return true;
+				}
+
+				if (
+					parent?.type !== "Property" ||
+					parent.value !== objectExpression
+				) {
+					return false;
+				}
+
+				property = parent;
+				objectExpression = property.parent;
+			}
+
+			return false;
+		}
+
+		// Type predicates (`x is Foo`) require a positional subject by language
+		// rule, so the readability/evolution argument doesn't apply. AGENTS.md
+		// carves these out explicitly.
+		function isTypePredicate(node) {
+			return node.returnType?.typeAnnotation?.type === "TSTypePredicate";
+		}
+
+		function reportIfNeeded(node) {
+			if (
+				node.params.length <= 1 ||
+				isDirectCallback(node) ||
+				isInlineOptionCallback(node) ||
+				isTypePredicate(node)
+			) {
+				return;
+			}
+
+			// Report from the function's first line through params[1] so a
+			// conventional `// eslint-disable-next-line` placed above the
+			// declaration suppresses the violation. The directive matches
+			// against `loc.start.line`, which must land on the function
+			// declaration line — not on a later parameter row.
+			context.report({
+				node,
+				loc: {
+					start: node.loc.start,
+					end: node.params[1].loc.end,
+				},
+				messageId: "preferObjectParams",
+			});
+		}
+
+		return {
+			ArrowFunctionExpression: reportIfNeeded,
+			FunctionDeclaration: reportIfNeeded,
+			FunctionExpression: reportIfNeeded,
+		};
+	},
+};