Arrow function is not a function

Question

I'm getting the error TypeError: f is not a function for the following: What am I doing wrong?

var expressws = require("express");
var appws = expressws();
var expressWs = require('express-ws')(appws);
function x(ws)
{
 console.log("send");
}
function loop(f,t)
{
 setTimeout(() => loop(), t);
 f();
}
appws.ws('/', function(ws, req) {
 ws.on('message', function(msg){
 var data = JSON.parse(msg);
 if(data.action == "Logged in"){
 loop(() => x(ws),1000);
 }
 });

});

• Samir: You are calling a function which is not present in the code . In this line. function loop(f,t){ setTimeout(() => loop(), t);f();}.
• hawk: setTimeout(() => { loop(f,t); }, t);

Answer 1

The following indirect recursive call passes nothing as an argument to loop, hence the error.

setTimeout(() => loop(/* should pass two arguments here */), t);

Answer 2

You need to pass arguments into loop function

setTimeout(() => loop(f, t), t);

another approach is

setTimeout(loop.bind(null, f, t), t);

or lodash version

_.delay(loop, t, f, t);