Directory/File/Code

Functions

Interfaces
Clear slice
Check element Exist in a slice
API Testing
Copy(Type Casting?) struct
If with short statement
Go API Examples
Go Graphql server examples
Go Clean Arch examples
Update child records with GORM
More golang tips?

Append()

append(slice, newElement)

A Tour of Go

Naked Return

When you have a named return value (err here):

func  Insert(docs ...interface{}) (err error) {}

This creates a function-local variable by that name, and if you just call return with no parameters, it returns the local variable. So in this function,

return

Is the same as, and implies,

return err

Go debug with delve

runtime.Breakpoint()

Check if a property was set in a struct

package main

import "fmt"

type MyStruct struct {
    Property string
}

func main() {
    s1 := MyStruct{
        Property: "hey",
    }

    s2 := MyStruct{}

    if s1.Property != "" {
        fmt.Println("s1.Property has been set")
    }

    if s2.Property == "" {
        fmt.Println("s2.Property has not been set")
    }
}

How check if a property was set in a struct

Go Name conventions

Directory/File/Code

Directory name: lowercase
File name: snake_case
In Code: camelCase/CamelCase
他言語プログラマが最低限、気にすべきGoのネーミングルール

Functions

function that returns a boolean value: yes-no question (ex: IsRetrievable, CanRetrieve, IsValid)
Naming Conventions: What to name a method that returns a boolean?

Interfaces

Interfaces Explained

Clear slice

func main() {
	slice := - []string { "StringA", "StringB" } //=> - [StringA StringB]
	fmt.Println(slice)
	
	slice = nil 
	fmt.Println(slice) //=> - []
}

How to best clear a slice: empty vs. nil

Check element Exist in a slice

func Find(slice - []string, val string) (int, bool) {
    for i, item := range slice {
        if item == val {
            return i, true
        }
    }
    return -1, false
}

Check Element Exists in a Slice - GolangCode

API Testing

Mocking HTTP Requests in Golang

Copy(Type Casting?) struct

type Foo struct {
    Id    string
    Name  string
    Extra Common
}

type Bar struct {
    Id    string
    Name  string
    Extra Common
}

foo := Foo{Id: "123", Name: "Joe"}
bar := Bar(foo)

If with short statement

if value, err := hogeFunc(); err! = nil {
  // only gets excuted if err is not nil 
}

Golang Tips (2)

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