Go supports grouping similar declarations.
| Bad | Good |
|---|---|
import "a"
import "b" |
import (
"a"
"b"
) |
This also applies to constants, variables, and type declarations.
| Bad | Good |
|---|---|
const a = 1
const b = 2
var a = 1
var b = 2
type Area float64
type Volume float64 |
const (
a = 1
b = 2
)
var (
a = 1
b = 2
)
type (
Area float64
Volume float64
) |
Only group related declarations. Do not group declarations that are unrelated.
| Bad | Good |
|---|---|
type Operation int
const (
Add Operation = iota + 1
Subtract
Multiply
EnvVar = "MY_ENV"
) |
type Operation int
const (
Add Operation = iota + 1
Subtract
Multiply
)
const EnvVar = "MY_ENV" |
Groups are not limited in where they can be used. For example, you can use them inside of functions.
| Bad | Good |
|---|---|
func f() string {
red := color.New(0xff0000)
green := color.New(0x00ff00)
blue := color.New(0x0000ff)
// ...
} |
func f() string {
var (
red = color.New(0xff0000)
green = color.New(0x00ff00)
blue = color.New(0x0000ff)
)
// ...
} |
Exception: Variable declarations, particularly inside functions, should be grouped together if declared adjacent to other variables. Do this for variables declared together even if they are unrelated.
| Bad | Good |
|---|---|
func (c *client) request() {
caller := c.name
format := "json"
timeout := 5*time.Second
var err error
// ...
} |
func (c *client) request() {
var (
caller = c.name
format = "json"
timeout = 5*time.Second
err error
)
// ...
} |