Go Best Practices

Always Handle Errors

Idiomatic Go treats every returned error as something to actively check, not an optional detail -- either handle it immediately, or explicitly wrap and propagate it up to a caller that can.

Example: Always Handle Errors

package main

import (
	"fmt"
	"strconv"
)

func parseAge(input string) (int, error) {
	age, err := strconv.Atoi(input)
	if err != nil {
		return 0, fmt.Errorf("invalid age %q: %w", input, err)
	}
	return age, nil
}

func main() {
	age, err := parseAge("thirty")
	if err != nil {
		fmt.Println("error:", err)
		return
	}
	fmt.Println("age:", age)
}

Favor Early Returns Over Deep Nesting

Handling error and edge cases with an early return at the top of a function keeps the main logic at a single indentation level, which is generally easier to read than deeply nested if/else chains.

Example: Favor Early Returns Over Deep Nesting

package main

import "fmt"

func classify(age int) string {
	if age < 0 {
		return "invalid"
	}
	if age < 13 {
		return "child"
	}
	if age < 20 {
		return "teen"
	}
	return "adult"
}

func main() {
	fmt.Println(classify(15))
	fmt.Println(classify(-1))
}

Accept Interfaces, Return Concrete Types

A common Go guideline is for functions to accept the smallest interface that satisfies their needs (making them flexible for callers), while returning a concrete type (making the result easy to work with directly).

Example: Accept Interfaces, Return Concrete Types

package main

import (
	"fmt"
	"strings"
)

func wordCount(r *strings.Reader) int {
	buf := make([]byte, r.Len())
	r.Read(buf)
	return len(strings.Fields(string(buf)))
}

func main() {
	r := strings.NewReader("Go favors small interfaces")
	fmt.Println(wordCount(r))
}

Keep Formatting Consistent

Running gofmt and go vet before committing catches formatting inconsistencies and likely bugs automatically, keeping the whole codebase in one consistent, machine-verified style rather than relying on manual review.

Note: Add 'gofmt -l .' and 'go vet ./...' to a pre-commit hook or CI pipeline to enforce this automatically.

Example: Keep Formatting Consistent

gofmt -l .
go vet ./...