select-outside-brackets and select-scope commands, built using Bracket Matcher’s select-inside-brackets.

init.js

'use babel';

import {Range} from 'atom';

atom.commands.add('atom-text-editor', 'editor:select-outside-brackets', function () {
  const editor = atom.workspace.getActiveTextEditor();
  const initial = editor && editor.getSelectedBufferRange().freeze();

  atom.commands.dispatch(editor.element, 'bracket-matcher:select-inside-brackets');

  const range = editor && editor.getSelectedBufferRange();
  if (!range.isEqual(initial)) {
    const newRange = new Range(range.start.traverse([0, -1]), range.end.traverse([0, 1]));
    editor.setSelectedBufferRange(newRange);
  }
});

atom.commands.add('atom-text-editor', 'editor:select-scope', function () {
  const editor = atom.workspace.getActiveTextEditor();
  const cursor = editor && editor.getLastCursor();
  const selectionRange = editor && editor.getSelectedBufferRange().freeze();
  const position = cursor && cursor.getBufferPosition();

  for (const scope of cursor ? cursor.getScopeDescriptor().getScopesArray().slice().reverse() : []) {
    const scopeRange = editor.bufferRangeForScopeAtPosition(scope, position);
    if (scopeRange && scopeRange.containsRange(selectionRange) && !scopeRange.isEqual(selectionRange)) {
      editor.setSelectedBufferRange(scopeRange);
      return;
    }
  }
});