Functions

Declaring functions with typed parameters and results, and passing functions as values.

A function names its inputs and outputs with types. Go functions are values, so a function can be passed to another function as behavior.

This example declares a function and passes another function to it:

package main
 
import "fmt"
 
func double(n int) int {
    return n * 2
}
 
func apply(value int, transform func(int) int) int {
    return transform(value)
}
 
func main() {
    fmt.Println(apply(4, double)) // 8
}

In production

Keep helpers focused and return explicit values. For operations that can fail, Go commonly returns a value and an error; see Multiple Return Values.

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