CODEWITHSUNDEEP
javascriptnode.jsexpresssocketssocket.io
Alk
Alk

Reputation: 5557

Breaking Down JS Functions

I'm trying to simplify my code and break it down into multiple files. For example, I managed to do: 

socket.once("disconnect", disconnectSocket);

and then have a separate function called disconnectSocket which can access the socket object as follows: 

const disconnectSocket = socket => {
  ....
};

I'm trying to do something similar with this pattern: 

socket.on(EVENT_NAME, params => {
   ...
});

where instead I can do: 

socket.on(EVENT_NAME, myFunc);

const myFunc = (socket, params) => {
  ...
}

but this is failing and saying params is undefined. What am I doing wrong?

Upvotes: 0

Views: 39

Answers (1)

Samuel Goldenbaum
Samuel Goldenbaum

Reputation: 18929

You can achieve this, but your function signature is incorrect. The handler will accept only one parameter. Note that a few of the built-in events like reconnect_failed don't pass any params.

Change your signature to:

socket.on(EVENT_NAME, myFunc);

const myFunc = (message) => {
  ...
}

If you want to access the socket, then do something like:

socket.on(EVENT_NAME, (message) => myFunc(socket, message));

const myFunc = (socket, message) => {
  ...
}

I use this exact pattern:

socket.on(constants.events.game.deployUnit, (message) => {
    deployUnit(socket, message);
});

socket.on(constants.events.game.skipOpponent, (message) => {
    skipOpponent(socket, message);
});

socket.on(constants.events.game.logDefenderKill, (message) => {
    logDefenderKill(socket, message);
});

Upvotes: 1

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