If Statements

In Go, if statements are similar to JavaScript/TypeScript, but with a few differences in syntax and usage. The basic structure of an if statement in Go is as follows:

if.go

x := 10
if x > 5 {
    fmt.Println("x is greater than 5")
} else if x < 5 {
    fmt.Println("x is less than 5")
} else {
    fmt.Println("x is equal to 5")
}

Note that there are no parentheses around the condition in the if statement!

Note

Curly braces {} are required in Go, even for single-line statements.

Variable Declaration in If Statements

Unlike JavaScript, in Go, you can declare a variable in the if statement using the shorthand variable declaration syntax :=. This variable will be scoped to the if statement and will not be accessible outside of it!

if_short.go

x := 10
if y := x * 2; y > 10 {
    fmt.Println("y is greater than 10")
} else {
    fmt.Println("y is less than or equal to 10")
}

Given the following TypeScript code:

lookup.ts

let myMap: Record<string, number> = {
    apple: 1,
    banana: 2
};

let count = myMap["apple"];

if (count != undefined) {
    console.log(`Apple count: ${count}`);
} else {
    console.log("Apple not found");
}

This can be elegantly rewritten in Go as:

lookup.go

myMap := map[string]int{"apple": 1, "banana": 2}

if count, exist := myMap["apple"]; exist {
    fmt.Printf("Apple count: %d\n", count) // count is 1, exist is true
} else {
    fmt.Println("Apple not found") // count is 0 (zero value for int), exist is false
}