How to get channelid in pubnub subscribe/or publish function?

Question

This my subscribe code i want to get the channelid so i used this.channel in the code but i got undefined. Is there any way that i can get channelid

pubnub.subscribe({
    channel: changing dynamically,
    presence: function (m) {
        console.log(m)
    },
    message: function (m) {
        console.log(m);
        console.log("Channel ==" + this.channel)
    },
    error: function (error) {
        // Handle error here
        console.log(JSON.stringify(error));
    }
})

result: Channel==undefined

Answer 1

Looking at the fine manual, this should work:

pubnub.subscribe({
    channel: changing dynamically,
    presence: function (m) {
        console.log(m)
    },
    message: function (m, env, channel) {
        console.log(m);
        console.log("Channel ==" + channel)
    },
    error: function (error) {
        // Handle error here
        console.log(JSON.stringify(error));
    }
})

In other words, the channel is passed as argument to the message callback.

The most likely reason for this.channel being undefined is that the message callback isn't called in the context of the object that is passed to pubnub.subscribe().