what is the function of the word return?

programming
1

I’m new to programming and I don’t understand how and why return is used. Could you explain it to me? preferably with an example, I’m a bit dumb :slight_smile:

2

Hey Dude,

Functions don’t need to return anything unless you are chaining functions together.

This means that function A relies on the value of function B running and "returning" a value …

This is usually so that you don’t have to write 1 big massive function for your entire program and also:

  • Code readabilty
  • Testing
  • Re-use
  • Control flow
  • understandable logic
  • So your head doesn’t explode…

Basically when you are chaining functions you’re:

  • Running a function and saving it to a variable (temporary or permanent variable)
  • Running another function with the result of the first function (saved in the variable)
  • Repeat until you do something with the result

If you don’t return a "value" from any function in the “chain” what will happen is:

  • the variable storing the function result will be undefined
  • the next function in the chain will try to run with undefinedas its main argument
  • that function will probably throw an error
  • you wont be able to continue with the chain and get a result

This chaining is also called piping.

Here’s a basic example of it with some simple addition.
(this will run in the browser console)

Try to wrap your head around the function stepper at the start


let object = {
  value1: undefined,
}

let add1 = function(x){
  return x + 1;
}

let add2 = function(x){
  return x + 2;
}

let add3 = function(x){
  return x + 3
}

// does nothing returns x
let returnX = function(x){
  return x
}

let noReturn = function(x){
   object.value1 = x
}

// pipes a number through an array of functions
let pipe = function(number, array){
  let accumulator = number;
  for(let fn of array){
    accumulator = fn(accumulator);
  }
  console.log(accumulator)
  return accumulator
}
// does the same as pipe but its hard coded without an array of functions
let stepper = function(x){
  let a = add1(x);
  let b = add2(a);
  let c = add3(b);
  console.log(c)
  return c 
}

pipe(5, [add1,add2,add3]) // returns 11
pipe(5,[add1,add2, add3,returnX]) // returns 11 
pipe(5, [add1,add2,add3,noReturn]) // returns undefined 
stepper(5)// returns 11
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