question regarding functions in js

What is the difference between assigning a variable to a function and vice versa?

3 Replies

Joao•5w ago

Do you have a specific example in mind? That question is not very intuitive: you can assign a function to a variable (that's what variables are for - storing values) but you cannot assign a variable to a function.

theboyduddus•5w ago

i meant: what is the difference between assigning a variable to a function and not assigning a variable to a function

13eck•5w ago

Do you mean the difference between

function someFunc(x) {
  return x+2;
}

function someFunc(x) {
  return x+2;
}

and

const funcSome = function(x) {
  return x+2;
}

const funcSome = function(x) {
  return x+2;
}

? If so, the difference is hoisting. When you use the function keyword the function is "hoisted" to the top of the stack. Normally JS files are read from top to bottom. Meaning you need to declare a variable or function before it's used, but a hoisted function can be used before it's declared. A function assigned to a variable is not hoisted, so it can't be used before it's declared. But on the flip side, if you declare the function using const you won't be able to accidentally overwrite the function later. Any function declared using the function keyword is mutable: it can be changed to another function or even a non-function variable! Because of this, I much prefer to declare all my functions using const and putting them at the top of my JS file. I've had too many situations where I thought I was coming up with a new function name but was overwriting an existing function (or overwriting a function with a variable!). So I don't take any chances anymore and just const all the things.

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question regarding functions in js