index: export a function to re-initialize mocks (#98)

* index: export a function to re-initialize mocks

Signed-off-by: Nick Santos <nick.santos@docker.com>

* Update src/index.js

Co-authored-by: Jon Dufresne <jon.dufresne@gmail.com>

* update type declaration

Signed-off-by: Nick Santos <nick.santos@docker.com>

* response to comments

Signed-off-by: Nick Santos <nick.santos@docker.com>

* response to comments

Signed-off-by: Nick Santos <nick.santos@docker.com>

Signed-off-by: Nick Santos <nick.santos@docker.com>
Co-authored-by: Jon Dufresne <jon.dufresne@gmail.com>

.gitignore

@@ -5,3 +5,6 @@ coverage
 package-lock.json
 yarn.lock
 lib
+.yarn
+.pnp.cjs
+.pnp.loader.mjs

README.md

@@ -63,6 +63,20 @@ Add that file to your `setupFiles` array:
 }
 ```
 
+## Reset
+
+If you reset the jest mocks (for example, with `jest.resetAllMocks()`), you can
+call `setupJestCanvasMock()` to re-create it.
+
+```
+import { setupJestCanvasMock } from 'jest-canvas-mock';
+
+beforeEach(() => {
+  jest.resetAllMocks();
+  setupJestCanvasMock();
+});
+```
+
 ## Mock Strategy
 
 This mock strategy implements all the canvas functions and actually verifies the parameters. If a

__tests__/index.js

@@ -2,7 +2,7 @@
  * test canvas
  */
 
-import { ver } from '../src';
+import { ver, setupJestCanvasMock } from '../src';
 import pkg from '../package.json';
 
 let canvas;
@@ -16,3 +16,14 @@ describe('canvas', () => {
     expect(ver).toBe(pkg.version);
   });
 });
+
+describe('setupJestCanvasMock', () => {
+  it('should setup after resetAllMocks', () => {
+    jest.resetAllMocks();
+    expect(document.createElement('canvas').getContext('2d')).toBe(undefined);
+    setupJestCanvasMock();
+    expect(document.createElement('canvas').getContext('2d')).toHaveProperty(
+      'createImageData'
+    );
+  });
+});

src/index.js

@@ -12,3 +12,7 @@ if (typeof window !== 'undefined') {
 }
 
 export const ver = '__VERSION__';
+
+export function setupJestCanvasMock(window) {
+  mockWindow(window || global.window);
+}

types/index.d.ts

@@ -1,3 +1,5 @@
+export function setupJestCanvasMock(window?: Window) {}
+
 export interface CanvasRenderingContext2DEvent {
   /**
    * This is the type of canvas event that occurred.