refactor: constants

Author: mdjastrzebski

src/__tests__/render.test.tsx

@@ -1,8 +1,9 @@
 /* eslint-disable no-console */
 import * as React from 'react';
 import { Pressable, Text, TextInput, View } from 'react-native';
-import { getConfig, resetToDefaults } from '../config';
-import { fireEvent, render, RenderAPI, screen } from '..';
+import { getConfig } from '../config';
+import { CONTAINER_TYPE } from '../renderer/contants';
+import { fireEvent, render, type RenderAPI, screen, resetToDefaults } from '..';
 
 const PLACEHOLDER_FRESHNESS = 'Add custom freshness';
 const PLACEHOLDER_CHEF = 'Who inspected freshness?';
@@ -172,7 +173,7 @@ test('returns container', () => {
   render(<View testID="inner" />);
 
   expect(screen.container).toBeDefined();
-  expect(screen.container.type).toBe('CONTAINER');
+  expect(screen.container.type).toBe(CONTAINER_TYPE);
   expect(screen.container.props).toEqual({});
 });
 

src/helpers/component-tree.ts

@@ -1,11 +1,12 @@
+import { CONTAINER_TYPE } from '../renderer/contants';
 import { HostElement } from '../renderer/host-element';
 
 /**
  * Checks if the given element is a host element.
  * @param element The element to check.
  */
 export function isValidElement(element?: HostElement | null): element is HostElement {
-  return typeof element?.type === 'string' && element.type !== 'CONTAINER';
+  return typeof element?.type === 'string' && element.type !== CONTAINER_TYPE;
 }
 
 /**

src/renderer/contants.ts

@@ -0,0 +1 @@
+export const CONTAINER_TYPE = 'CONTAINER';

src/renderer/host-element.ts

@@ -1,4 +1,6 @@
+import { CONTAINER_TYPE } from './contants';
 import { Container, Instance, TextInstance } from './reconciler';
+import { JsonNode, renderToJson } from './render-to-json';
 
 export type HostNode = HostElement | string;
 export type HostElementProps = Record<string, any>;
@@ -13,7 +15,7 @@ export class HostElement {
   }
 
   get type(): string {
-    return this.instance.tag === 'INSTANCE' ? this.instance.type : 'CONTAINER';
+    return this.instance.tag === 'INSTANCE' ? this.instance.type : CONTAINER_TYPE;
   }
 
   get props(): HostElementProps {
@@ -53,6 +55,10 @@ export class HostElement {
     return Symbol.for('react.test.json');
   }
 
+  toJSON(): JsonNode | null {
+    return renderToJson(this.instance);
+  }
+
   static fromContainer(container: Container): HostElement {
     const hostElement = instanceToHostElementMap.get(container);
     if (hostElement) {

src/renderer/render-to-json.ts

@@ -1,3 +1,4 @@
+import { CONTAINER_TYPE } from './contants';
 import { Container, Instance, TextInstance } from './reconciler';
 
 export type JsonNode = JsonInstance | string;
@@ -70,7 +71,7 @@ export function renderToJson(instance: Container | Instance | TextInstance): Jso
       }
 
       const result = {
-        type: 'CONTAINER',
+        type: CONTAINER_TYPE,
         props: {},
         children: renderedChildren,
         $$typeof: Symbol.for('react.test.json'),

src/renderer/renderer.test.tsx

@@ -6,6 +6,10 @@ function Passthrough({ children }: { children: React.ReactNode }) {
   return children;
 }
 
+function RendersNull() {
+  return null;
+}
+
 test('renders View', () => {
   const renderer = createRenderer();
   renderer.render(<View />);
@@ -82,6 +86,15 @@ test('returns container view', () => {
   `);
 });
 
+test('returns null when rendering indirectly null', () => {
+  const renderer = createRenderer();
+  renderer.render(<RendersNull />);
+
+  expect(renderer.container).toMatchInlineSnapshot(`<CONTAINER />`);
+  expect(renderer.root).toBeNull();
+  expect(renderer.toJSON()).toBeNull();
+});
+
 test('throws when rendering string outside of Text', () => {
   jest.spyOn(console, 'error').mockImplementation(() => {});