message: fix: hack for babel < 6 so that breakpoints do work
  It fixes but AFAIK there is badly no way of doing a test for that
diff: @@ -26,6 +26,25 @@ function importBabelDeps() {
  if (babel) return; // tslint:disable-line
  // we must use babel until we handle hoisting of jest.mock() internally
  babel = importBabelCore();
  +
  + // HACK: there is an issue still open in babel 6, this is a hack to bypass it
  + // and fix our issue #627
  + // Issue in babel: https://github.com/babel/babel/issues/6577
  + if (babel.version && parseInt(babel.version.split('.')[0], 10) === 6) {
  + const File = require('babel-core/lib/transformation/file/index.js').File;
  + File.prototype.initOptions = (original => {
  + return function(opt) {
  + const before = opt.sourceMaps;
  + const result = original.apply(this, arguments);
  + if (opt.sourceMaps != null && opt.sourceMaps !== result.sourceMaps) {
  + result.sourceMaps = opt.sourceMaps;
  + }
  + return result;
  + };
  + })(File.prototype.initOptions);
  + }
  + // end of HACK
  +
  istanbulPlugin = importBabelPluginIstanbul();
  jestPreset = importBabelPresetJest();
  }
  