Actions: expand isInputError to accept unknown

.changeset/nasty-poems-juggle.md

@@ -0,0 +1,18 @@
+---
+'astro': patch
+---
+
+Expands the `isInputError()` utility from `astro:actions` to accept errors of any type. This should now allow type narrowing from a try / catch block.
+
+```ts
+// example.ts
+import { actions, isInputError } from 'astro:actions';
+
+try {
+  await actions.like(new FormData());
+} catch (error) {
+  if (isInputError(error)) {
+    console.log(error.fields);
+  }
+}
+```

package.json

@@ -24,6 +24,7 @@
     "test:citgm": "pnpm -r --filter=astro test",
     "test:match": "cd packages/astro && pnpm run test:match",
     "test:unit": "cd packages/astro && pnpm run test:unit",
+    "test:types": "cd packages/astro && pnpm run test:types",
     "test:unit:match": "cd packages/astro && pnpm run test:unit:match",
     "test:smoke": "pnpm test:smoke:example && pnpm test:smoke:docs",
     "test:smoke:example": "turbo run build --concurrency=100% --filter=\"@example/*\"",

packages/astro/package.json

@@ -114,12 +114,13 @@
     "build:ci": "pnpm run prebuild && astro-scripts build \"src/**/*.{ts,js}\" && pnpm run postbuild",
     "dev": "astro-scripts dev --copy-wasm --prebuild \"src/runtime/server/astro-island.ts\" --prebuild \"src/runtime/client/{idle,load,media,only,visible}.ts\" \"src/**/*.{ts,js}\"",
     "postbuild": "astro-scripts copy \"src/**/*.astro\" && astro-scripts copy \"src/**/*.wasm\"",
-    "test": "pnpm run test:node",
+    "test": "pnpm run test:node && pnpm run test:types",
     "test:match": "pnpm run test:node --match",
     "test:e2e": "pnpm test:e2e:chrome && pnpm test:e2e:firefox",
     "test:e2e:match": "playwright test -g",
     "test:e2e:chrome": "playwright test",
     "test:e2e:firefox": "playwright test --config playwright.firefox.config.js",
+    "test:types": "tsc --project tsconfig.tests.json",
     "test:node": "astro-scripts test \"test/**/*.test.js\""
   },
   "dependencies": {
@@ -215,6 +216,7 @@
     "astro-scripts": "workspace:*",
     "cheerio": "1.0.0-rc.12",
     "eol": "^0.9.1",
+    "expect-type": "^0.19.0",
     "mdast-util-mdx": "^3.0.0",
     "mdast-util-mdx-jsx": "^3.1.2",
     "memfs": "^4.9.3",

packages/astro/src/actions/runtime/utils.ts

@@ -31,3 +31,14 @@ export async function getAction(
 	}
 	return actionLookup;
 }
+
+/**
+ * Used to preserve the input schema type in the error object.
+ * This allows for type inference on the `fields` property
+ * when type narrowed to an `ActionInputError`.
+ *
+ * Example: Action has an input schema of `{ name: z.string() }`.
+ * When calling the action and checking `isInputError(result.error)`,
+ * `result.error.fields` will be typed with the `name` field.
+ */
+export type ErrorInferenceObject = Record<string, any>;

packages/astro/src/actions/runtime/virtual/server.ts

@@ -1,13 +1,7 @@
 import { z } from 'zod';
 import { type ActionAPIContext, getApiContext as _getApiContext } from '../store.js';
-import { type MaybePromise } from '../utils.js';
-import {
-	ActionError,
-	ActionInputError,
-	type ErrorInferenceObject,
-	type SafeResult,
-	callSafely,
-} from './shared.js';
+import type { ErrorInferenceObject, MaybePromise } from '../utils.js';
+import { ActionError, ActionInputError, type SafeResult, callSafely } from './shared.js';
 
 export * from './shared.js';
 

packages/astro/src/actions/runtime/virtual/shared.ts

@@ -1,5 +1,5 @@
 import type { z } from 'zod';
-import type { MaybePromise } from '../utils.js';
+import type { ErrorInferenceObject, MaybePromise } from '../utils.js';
 
 type ActionErrorCode =
 	| 'BAD_REQUEST'
@@ -40,8 +40,6 @@ const statusToCodeMap: Record<number, ActionErrorCode> = Object.entries(codeToSt
 	{}
 );
 
-export type ErrorInferenceObject = Record<string, any>;
-
 export class ActionError<T extends ErrorInferenceObject = ErrorInferenceObject> extends Error {
 	type = 'AstroActionError';
 	code: ActionErrorCode = 'INTERNAL_SERVER_ERROR';
@@ -85,6 +83,10 @@ export class ActionError<T extends ErrorInferenceObject = ErrorInferenceObject>
 
 export function isInputError<T extends ErrorInferenceObject>(
 	error?: ActionError<T>
+): error is ActionInputError<T>;
+export function isInputError(error?: unknown): error is ActionInputError<ErrorInferenceObject>;
+export function isInputError<T extends ErrorInferenceObject>(
+	error?: unknown | ActionError<T>
 ): error is ActionInputError<T> {
 	return error instanceof ActionInputError;
 }

packages/astro/test/types/is-input-error.ts

@@ -0,0 +1,31 @@
+import { expectTypeOf } from 'expect-type';
+import { isInputError, defineAction } from '../../dist/actions/runtime/virtual/server.js';
+import { z } from '../../zod.mjs';
+import { describe, it } from 'node:test';
+
+const exampleAction = defineAction({
+	input: z.object({
+		name: z.string(),
+	}),
+	handler: () => {},
+});
+
+const result = await exampleAction.safe({ name: 'Alice' });
+
+describe('isInputError', () => {
+	it('isInputError narrows unknown error types', async () => {
+		try {
+			await exampleAction({ name: 'Alice' });
+		} catch (e) {
+			if (isInputError(e)) {
+				expectTypeOf(e.fields).toEqualTypeOf<Record<string, string[] | undefined>>();
+			}
+		}
+	});
+
+	it('`isInputError` preserves `fields` object type for ActionError objects', async () => {
+		if (isInputError(result.error)) {
+			expectTypeOf(result.error.fields).toEqualTypeOf<{ name?: string[] }>();
+		}
+	});
+});

packages/astro/tsconfig.tests.json

@@ -0,0 +1,9 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "include": ["test/types"],
+  "compilerOptions": {
+    "allowJs": true,
+    "emitDeclarationOnly": false,
+    "noEmit": true,
+  }
+}