Getting Cannot read property 'forEach' of undefined

[sgkhode]

I am getting error from this piece of code.
` _handleMessage (json) {
let entries = json.entry

entries.forEach((entry) => {
  let events = entry.messaging

  events.forEach((event) => {
    // handle inbound messages and echos
    if (event.message) {
      if (event.message.is_echo) {

`
events is undefined.

What could be the issue here?

[unandreshevia]

I am getting the same error and it happens when you receive postback-type of message from Facebook.