README.md

GoError v1.0.0

GoError is a simple and pluggable Go package that allows developers to create and handle errors in Go more efficiently and gracefully, while also preserving the context of every error.

Why use this package?

• Plug and Play (compatible with existing go errors package)
• Allows you to specify error types
• Easy conversion of error into Map or JSON.
• Add context to error for passing the human-readable error message to client-side applications.
• Wraps and unwraps error stack.

Documentation

Let's look at some code snippets. But before this, make sure to download the package using

go get -v github.com/dipaksaini98/goerror

and import the package as

import  (
    errors "github.com/dipaksaini98/goerror"
)

Create error

Syntax:

New(message string, error_type Type) error

1. Create an error without an error type

Example:

err := errors.New("error message", nil)
fmt.Println(err)
>> Error message

Note: when you don't specify any error type NoType is set by default.

2. Create an error with an error type

Example:

err :=  errors.New("error message", &errors.BadRequest)
fmt.Println(err)
>> Error message

Add context to an error

Syntax:

SetContext(error_object error, key string, value interface{}) error

Example:

err :=  errors.New("programmer friendly error message", nil)
err := errors.SetContext(err, "user-email", "email is missing")

---

err :=  errors.New("programmer friendly error message", nil)
err := errors.SetContext(err, "email", map[string]string{"email_domain": "invalid email domain", "email_local_part": "invalid local part (must start with `a` alphabet)"})

Get error context

Syntax:

GetContext(error_object error) map[string]interface{}

Example:

ctx :=  errors.GetContext(error)

Add/update error type

Syntax:

SetType(error_object error, type *Type) error

Example:

err :=  errors.SetType(err, &errors.NotFound)

---

var customErrorType errors.Type = "CustomErrorType"
err :=  errors.SetType(err, &customErrorType)

List of predefined error types:

 1. NoType
 2. BadRequest
 3. NotFound
 4. DBError
 5. Unauthorized
 6. PermissionDenied
 7. SomethingWentWrong

Get error type

Syntax:

GetType(error_object error) Type

Example:

errType :=  errors.GetType(err)

Create a custom error type

Example:

var CustomErrorType errors.Type = "CustomErrorType"

Compare two errors (errors Is)

Syntax:

errors.Is(error_1 error, error_2 error) bool

Example:

err1 := errors.New("error1", nil)
err2 := errors.New("error2", nil)
isSame := errors.Is(err1, err2)

fmt.Println(isSame)
>>false

err3 := err1
isSame = errors.Is(err3, err1)

fmt.Println(isSame)
>>true

Compare error types (errors As)

Syntax:

errors.As(error_1 error, error_2 error) bool

Example:

err1 := errors.New("error1", nil)
err2 := errors.New("error2", nil)
isSameType := errors.As(err1, err2)

fmt.Println(isSameType)
>>true 
// Because of NoType (default)

err3 := errors.New("error2", &errors.BadRequest)
isSameType = errors.As(err3, err1)

fmt.Println(isSameType)
>>false

Convert error to Map

Syntax:

errors.Map(error_1 error) map[string]interface{}

Example:

err1 := errors.New("error1", nil)
errMap := errors.Map(err1)
fmt.Println(errMap)
>> map[message:error1 type:NoType]
err1 = errors.SetContext(err1, "email", "email not found")
errMap = errors.Map(err1)
fmt.Println(errMap)
>> map[field:email message:email not found type:NoType]

Convert error to JSON

Syntax:

errors.Map(error_1 error) map[string]interface{}

Example:

err1 := errors.New("error1", nil)
errJSON := errors.JSON(err1)

fmt.Println(string(errJSON))
>> {"message":"error1","type":"NoType"}

err1 = errors.SetContext(err1, "email", "email not found")
errJSON = errors.JSON(err1)

fmt.Println(string(errJSON))
>> {"field": "email", "message": "email not found", "type": "NoType"}