fix(jest-each) Throws an error when too much arguments are passed

CHANGELOG.md

@@ -9,6 +9,7 @@
 
 - `[expect]` Restore support for passing functions to `toHaveLength` matcher ([#9796](https://github.com/facebook/jest/pull/9796))
 - `[jest-changed-files]` `--only-changed` should include staged files ([#9799](https://github.com/facebook/jest/pull/9799))
+- `[jest-each]` `each` will throw an error when called with too many arguments ([#9818](https://github.com/facebook/jest/pull/9818))
 
 ### Chore & Maintenance
 

packages/jest-each/src/__tests__/__snapshots__/index.test.ts.snap

@@ -0,0 +1,3 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`throws an error when not called with the right number of arguments 1`] = `"\`.each\` must only be called with an Array or Tagged Template Literal."`;

packages/jest-each/src/__tests__/index.test.ts

@@ -32,3 +32,17 @@ describe('template', () => {
     });
   });
 });
+
+test('throws an error when not called with the right number of arguments', () => {
+  expect(() =>
+    each(
+      [
+        [1, 1, 2],
+        [1, 2, 3],
+        [2, 1, 3],
+      ],
+      'seems like a title but should not be here',
+      () => {},
+    ),
+  ).toThrowErrorMatchingSnapshot();
+});

packages/jest-each/src/index.ts

@@ -15,6 +15,13 @@ const install = (
   table: Global.EachTable,
   ...data: Global.TemplateData
 ) => {
+  const bindingWithArray = data.length === 0;
+  const bindingWithTemplate = Array.isArray(table) && !!(table as any).raw;
+  if (!bindingWithArray && !bindingWithTemplate) {
+    throw new Error(
+      '`.each` must only be called with an Array or Tagged Template Literal.',
+    );
+  }
   const test = (title: string, test: Global.EachTestFn, timeout?: number) =>
     bind(g.test)(table, ...data)(title, test, timeout);
   test.skip = bind(g.test.skip)(table, ...data);