Javascript Callback functions

A callback function in JavaScript is a function that receives an argument from another function and runs after the original function has finished running. It is a means of offering a function that can be used later or after an event has taken place.

syntax:

function functionA(param1, param2, callback) {
  // do something with param1 and param2
  // call the callback function
  callback();
}

function functionB() {
  console.log("This is the callback function");
}

functionA(1, 2, functionB);

Function A in the example above accepts the two arguments param1 and param2 as well as the callback function callback. Following some processing with parameters 1 and 2, the function then calls the callback function.

FunctionA receives a callback function, functionB, as an argument. This indicates that functionB will be executed after functionA has finished running and has reached the point at which the callback function is called.

Function B just logs a message to the terminal when it is executed. This demonstrates how, once the first function has finished running, the callback function may be used to carry out any kind of activity.

In asynchronous programming, when certain operations could take longer to complete and the execution of the code is not linear, callbacks are frequently utilized. By including a callback function, the longer operation can be delayed while the code continues to run, and the callback function can be used to handle the operation’s outcome.

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