tests

test/utils/isAction.spec.ts

@@ -0,0 +1,23 @@
+import { isAction } from 'redux'
+
+describe('isAction', () => {
+  it('should only return true for plain objects with a string type property', () => {
+    const actionCreator = () => ({ type: 'anAction' })
+    class Action {
+      type = 'totally an action'
+    }
+    const testCases: [action: unknown, expected: boolean][] = [
+      [{ type: 'an action' }, true],
+      [{ type: 'more props', extra: true }, true],
+      [{ type: 0 }, false],
+      [actionCreator(), true],
+      [actionCreator, false],
+      [Promise.resolve({ type: 'an action' }), false],
+      [new Action(), false],
+      ['a string', false]
+    ]
+    for (const [action, expected] of testCases) {
+      expect(isAction(action)).toBe(expected)
+    }
+  })
+})