code: function isHelper(node) {
    if (t.isMemberExpression(node)) {
      return isHelper(node.object) || isHelper(node.property);
    } else if (t.isIdentifier(node)) {
      return node.name === "require" || node.name[0] === "_";
    } else if (t.isCallExpression(node)) {
      return isHelper(node.callee);
    } else if (t.isBinary(node) || t.isAssignmentExpression(node)) {
      return t.isIdentifier(node.left) && isHelper(node.left) || isHelper(node.right);
    } else {
      return false;
    }
  }
docs: Test if a node is or has a helper.