chalk

Chalk

Easy to use terminal coloring module. It is written as a partial replacement for fmt (you can use Print, Sprint, Println, Sprintln, Printf, Sprintf) and have multiple ways of use.

This module has been written for Mac & Linux and not tested on Windows.

Formatter

You can call the name of color (Black, Red...) or format (Bold, Italic...) as module function. This will return a Formatter that has Print, Sprint, Println, Sprintln, Printf, Sprintf methods.

Basic Formatting

chalk.Bold().Println("bold text")
chalk.Red().Printf("red %d", 42)
chalk.GreenBackground().Print("green", "text")

Format Chaining

chalk.Bold().Cyan().Println("bold cyan text")
chalk.Red().Italic().Printf("red italic %d", 42)
chalk.GreenBackground().Bold().Print("green", "bold", "text")

As Variable

You can also "cook" Formatters to variable and reuse.

cyan := chalk.Cyan().Bold()
boldi := chalk.Bold().Italic()

for index, msg := range messages {
    boldi.Println(index)
    cyan.Println(msg)
}

Caching

If you are using just certain formatting all the time, it is better to use Cached Formatter instead. Cached Formatter has reduced overhead, but you will lose the ability to change it any further. Following methods are available on this formatter: Print, Sprint, Println, Sprintln, Printf, Sprintf & Set.

var (
    cyan = chalk.Cyan.Cached() // No longer editable, but faster
)

func PrintVeryLongListOfMessages() {
    for _, msg := range veryLongListOfMessages {
        cyan.Println(msg) // Same calls as on regular Formatter
    }
}

Set & Clear

You can call Set function on Formatter to set formatter's color format active until Clear or other formatting function is called.

// Set bold + italic formatting
chalk.Bold().Italic().Set()

// Print formatted messages
log.Println("Bold Italic formatted message 1")
log.Println("Bold Italic formatted message 2")
log.Println("Bold Italic formatted message 3")

// Add cyan formatting to previous formatting
// This becomes Bold+Italic+Cyan formatting in terminal
chalk.Cyan().Set() 

// Print newly formatted messages
log.Println("Bold Italic Cyan formatted message 1")

 // Clear all formatting
 // This sets terminal to default color formatting
chalk.Clear()

// Print non-formatted (or default formatted) message
log.Println("Non formatted message")

Disable/Enable coloring

You can temporarily disable/enable coloring with Disable() or Enable() functions. This only overrides behaviour and you can still use formatting functions as is, but they won't do any formating.

// Print bold text
chalk.Bold().Println("bold text")

// Disable formatting
chalk.Disable()

// Print non-bold text (because of disabled formatting)
chalk.Bold().Println("not-bold text")

// Enable formatting again
chalk.Enable()

// Print bold text
chalk.Bold().Println("bold text")

JSON Color formatting (Experimental)

If you are brave enough you can play with JSON(v interface{}) and JSON(v interface{}, prefix, indent string) function (similar signature to json.Marshal & json.MarshalIndent) that parses given value and reports new color formatted json. Output should be similar to that of json.Marshal*, but as stated before; This functionality is experimental and should mostly be used for debugging purposes.

Shorthand calls

You can call the Formatter functions with As prefix (AsBlack, AsRed, AsBold, AsItalic...) to directly report color formatted string. This shorthand syntax supports multiple arguments (just as most of fmt.Print* functions).

chalk.AsBold("bold text")
chalk.AsRed("red", 42)
chalk.AsGreenBackground("green", "text")

List of Colors & Formats

• Bold
• Faint
• Italic
• Underline
• BlinkSlow
• BlinkRapid
• ReverseVideo
• Concealed
• CrossedOut

• Black ⚫️
• Red 🔴
• Green 🍏
• Yellow 💛
• Blue 🔵
• Magenta 💜
• Cyan 🚙
• White ⚪️

• BlackBackground ⚫️
• RedBackground 🔴
• GreenBackground 🍏
• YellowBackground 💛
• BlueBackground 🔵
• MagentaBackground 💜
• CyanBackground 🚙
• WhiteBackground ⚪️

• BlackIntense ⚫️
• RedIntense 🔴
• GreenIntense 🍏
• YellowIntense 💛
• BlueIntense 🔵
• MagentaIntense 💜
• CyanIntense 🚙
• WhiteIntense ⚪️

• BlackIntenseBackground ⚫️
• RedIntenseBackground 🔴
• GreenIntenseBackground 🍏
• YellowIntenseBackground 💛
• BlueIntenseBackground 🔵
• MagentaIntenseBackground 💜
• CyanIntenseBackground 🚙
• WhiteIntenseBackground ⚪️