code: function globalizeDeclaration(node, bindings) {
    return node.declarations.map(declaration =>
      t.expressionStatement(
        t.assignmentExpression(
          "=",
          getAssignmentTarget(declaration.id, bindings),
          declaration.init || t.unaryExpression("void", t.numericLiteral(0))
        )
      )
    );
  }
docs: translates new bindings `var a = 3` into `self.a = 3` and existing bindings `var a = 3` into `a = 3` for re-assignments