Add render_utils.js for DRY-sake

Minor refactoring so custom renderers are
more DRY. Also cleaned up an origin() call

app/assets/javascripts/vue_shared/components/rich_content_editor/services/renderers/render_embedded_ruby_text.js

-import { buildUneditableTokens } from './build_uneditable_token';
+import { renderDefaultBlock } from './render_utils';
 
 const embeddedRubyRegex = /(^<%.+%>$)/;
 
@@ -6,8 +6,6 @@ const canRender = ({ literal }) => {
   return embeddedRubyRegex.test(literal);
 };
 
-const render = (_, { origin }) => {
-  return buildUneditableTokens(origin());
-};
+const render = renderDefaultBlock;
 
 export default { canRender, render };

app/assets/javascripts/vue_shared/components/rich_content_editor/services/renderers/render_identifier_paragraph.js

-import { buildUneditableOpenTokens, buildUneditableCloseToken } from './build_uneditable_token';
+import { renderEnterExitBlock } from './render_utils';
 
 const identifierRegex = /(^\[.+\]: .+)/;
 
@@ -10,7 +10,6 @@ const canRender = (node, context) => {
   return isIdentifier(context.getChildrenText(node));
 };
 
-const render = (_, { entering, origin }) =>
-  entering ? buildUneditableOpenTokens(origin()) : buildUneditableCloseToken();
+const render = renderEnterExitBlock;
 
 export default { canRender, render };

app/assets/javascripts/vue_shared/components/rich_content_editor/services/renderers/render_kramdown_list.js

-import { buildUneditableOpenTokens, buildUneditableCloseToken } from './build_uneditable_token';
+import { renderEnterExitBlock } from './render_utils';
 
 const isKramdownTOC = ({ type, literal }) => type === 'text' && literal === 'TOC';
 
@@ -21,7 +21,6 @@ const canRender = node => {
   return false;
 };
 
-const render = (_, { entering, origin }) =>
-  entering ? buildUneditableOpenTokens(origin()) : buildUneditableCloseToken();
+const render = renderEnterExitBlock;
 
 export default { canRender, render };

app/assets/javascripts/vue_shared/components/rich_content_editor/services/renderers/render_kramdown_text.js

-import { buildUneditableTokens } from './build_uneditable_token';
+import { renderDefaultBlock } from './render_utils';
 
 const kramdownRegex = /(^{:.+}$)/;
 
@@ -6,8 +6,6 @@ const canRender = ({ literal }) => {
   return kramdownRegex.test(literal);
 };
 
-const render = (_, { origin }) => {
-  return buildUneditableTokens(origin());
-};
+const render = renderDefaultBlock;
 
 export default { canRender, render };

app/assets/javascripts/vue_shared/components/rich_content_editor/services/renderers/render_utils.js

+import {
+  buildUneditableTokens,
+  buildUneditableOpenTokens,
+  buildUneditableCloseToken,
+} from './build_uneditable_token';
+
+export const renderDefaultBlock = (_, { origin }) => buildUneditableTokens(origin());
+
+export const renderEnterExitBlock = (_, { entering, origin }) =>
+  entering ? buildUneditableOpenTokens(origin()) : buildUneditableCloseToken();

spec/frontend/vue_shared/components/rich_content_editor/services/renderers/render_kramdown_list_spec.js

@@ -34,7 +34,11 @@ describe('Render Kramdown List renderer', () => {
   });
 
   describe('render', () => {
-    const origin = jest.fn();
+    let origin;
+
+    beforeEach(() => {
+      origin = jest.fn();
+    });
 
     it('should return uneditable open tokens when entering', () => {
       const context = { entering: true, origin };

spec/frontend/vue_shared/components/rich_content_editor/services/renderers/render_utils_spec.js

+import {
+  renderDefaultBlock,
+  renderEnterExitBlock,
+} from '~/vue_shared/components/rich_content_editor/services/renderers/render_utils';
+
+import { uneditableCloseToken } from './mock_data';
+
+describe('Render utils', () => {
+  describe('renderDefaultBlock', () => {
+    it('should...', () => {
+      const context = { origin: jest.fn() };
+      const result = renderDefaultBlock({}, context);
+
+      expect(context.origin).toHaveBeenCalled();
+      expect(result).toHaveLength(3);
+      expect(result[2]).toStrictEqual(uneditableCloseToken);
+    });
+  });
+
+  describe('renderEnterExitBlock', () => {
+    let origin;
+
+    beforeEach(() => {
+      origin = jest.fn();
+    });
+
+    it('should return two tokens as an array when entering', () => {
+      const context = { entering: true, origin };
+      const result = renderEnterExitBlock({}, context);
+
+      expect(context.origin).toHaveBeenCalled();
+      expect(result).toHaveLength(2);
+    });
+
+    it('should return a single closing token as an object when exiting', () => {
+      const context = { entering: false, origin };
+      const result = renderEnterExitBlock({}, context);
+
+      expect(context.origin).not.toHaveBeenCalled();
+      expect(result).toStrictEqual(uneditableCloseToken);
+    });
+  });
+});