Merge pull request #14645 from atom/jr-fix-observe-text-editor-methods

Fix observeTextEditors method in WorkspaceCenter

spec/workspace-center-spec.js

@@ -0,0 +1,31 @@
+/** @babel */
+
+const TextEditor = require('../src/text-editor')
+
+import {it, fit, ffit, fffit, beforeEach, afterEach} from './async-spec-helpers'
+
+describe('WorkspaceCenter', () => {
+  describe('.observeTextEditors()', () => {
+    it('invokes the observer with current and future text editors', () => {
+      const workspaceCenter = atom.workspace.getCenter()
+      const pane = workspaceCenter.getActivePane()
+      const observed = []
+
+      const editorAddedBeforeRegisteringObserver = new TextEditor()
+      const nonEditorItemAddedBeforeRegisteringObserver = document.createElement('div')
+      pane.activateItem(editorAddedBeforeRegisteringObserver)
+      pane.activateItem(nonEditorItemAddedBeforeRegisteringObserver)
+
+      workspaceCenter.observeTextEditors(editor => observed.push(editor))
+
+      const editorAddedAfterRegisteringObserver = new TextEditor()
+      const nonEditorItemAddedAfterRegisteringObserver = document.createElement('div')
+      pane.activateItem(editorAddedAfterRegisteringObserver)
+      pane.activateItem(nonEditorItemAddedAfterRegisteringObserver)
+
+      expect(observed).toEqual(
+        [editorAddedBeforeRegisteringObserver, editorAddedAfterRegisteringObserver]
+      )
+    })
+  })
+})

src/workspace-center.js

@@ -226,6 +226,25 @@ module.exports = class WorkspaceCenter {
     return this.paneContainer.onDidDestroyPaneItem(callback)
   }
 
+  // Extended: Invoke the given callback when a text editor is added to the
+  // workspace center.
+  //
+  // * `callback` {Function} to be called when panes are added.
+  //   * `event` {Object} with the following keys:
+  //     * `textEditor` {TextEditor} that was added.
+  //     * `pane` {Pane} containing the added text editor.
+  //     * `index` {Number} indicating the index of the added text editor in its
+  //        pane.
+  //
+  // Returns a {Disposable} on which `.dispose()` can be called to unsubscribe.
+  onDidAddTextEditor (callback) {
+    return this.onDidAddPaneItem(({item, pane, index}) => {
+      if (item instanceof TextEditor) {
+        callback({textEditor: item, pane, index})
+      }
+    })
+  }
+
   /*
   Section: Pane Items
   */