A function can have a return value.
By default a function returns undefined
.
If you want to return a value from it, you add a return
keyword with a value:
function test() {
// do something
return "hi!"
}
In your program you can assign the return value of the function to a variable, when you invoke the function:
function test() {
// do something
return "hi!"
}
const result = test()
result
now holds a string with the hi!
value.
One thing to note is that you can “return early” from a function, and this is very useful for example when you need to meet a condition before going on with your program:
function test(condition) {
if (condition === false) return
// do something
return "hi!"
}
const result = test(true)
You can only return one value from a function.
A “trick” to return multiple values from a function is to return an object, or an array, like this:
function test() {
return ["Flavio", 37]
}
Then you can call the function and save your array to a variable, or use array destructuring like this:
const [name, age] = test()
Lessons this unit:
0: | Introduction |
1: | Function parameters |
2: | ▶︎ Returning values from a function |
3: | Arrow functions |
4: | Nesting functions |
5: | Immediately-invoked functions |
6: | Recursive functions |