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The Styles API allows you to customize the colors, formatting, and visual appearance of log entries when using the TextFormatter. It leverages the lipgloss library to provide rich terminal styling.

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Styles Type

The Styles struct defines the visual appearance of all log components: 
type Styles struct {
    Timestamp lipgloss.Style  // Timestamp styling
    Caller    lipgloss.Style  // Caller location styling
    Prefix    lipgloss.Style  // Prefix styling
    Message   lipgloss.Style  // Message text styling
    Key       lipgloss.Style  // Field key styling
    Value     lipgloss.Style  // Field value styling
    Separator lipgloss.Style  // Key-value separator styling
    StackFunc lipgloss.Style  // Stack trace function styling
    StackFile lipgloss.Style  // Stack trace file styling
    
    // Map custom styles for specific levels
    Levels    map[Level]lipgloss.Style
    
    // Map custom styles for specific keys
    Keys      map[string]lipgloss.Style
    
    // Map custom styles for specific value keys
    Values    map[string]lipgloss.Style
    
    // Pre-rendered level strings for performance
    CachedLevelStrings map[Level]string
}

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DefaultStyles

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DefaultStyles()
*Styles
Returns the standard styling configuration with clean, color-coded defaults
func DefaultStyles() *Styles
Initializes and returns the default styling configuration used by Velo. The defaults provide:
  • Faint timestamps and callers
  • Bold, faint prefixes
  • Color-coded log levels (blue for Debug, green for Info, yellow for Warn, red for Error, purple for Fatal)
  • Faint field keys
  • Normal field values
Source: styles.go:55-103

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Example

// Get default styles
styles := velo.DefaultStyles()

// Customize timestamp color
styles.Timestamp = styles.Timestamp.Foreground(lipgloss.Color("240"))

// Customize error level to bright red
styles.Levels[velo.ErrorLevel] = lipgloss.NewStyle().
    SetString("ERROR").
    Bold(true).
    Foreground(lipgloss.Color("196"))

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SetDefaultStyles

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SetDefaultStyles(s *Styles)
void
Overrides the global default styles for all TextFormatter instances
func SetDefaultStyles(s *Styles)
Replaces the global default styles with a custom configuration. This affects all loggers using TextFormatter unless they have their own custom styles.
Call SetDefaultStyles() before creating any loggers to ensure consistent styling across your application.
Source: styles.go:108-120

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Example

// Create custom styles
customStyles := velo.DefaultStyles()

// Customize for dark terminal
customStyles.Message = customStyles.Message.Foreground(lipgloss.Color("252"))
customStyles.Key = customStyles.Key.Foreground(lipgloss.Color("240"))

// Apply globally
velo.SetDefaultStyles(customStyles)

// All new loggers will use custom styles
logger := velo.New(os.Stderr)

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Customization Examples

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Custom Level Colors

styles := velo.DefaultStyles()

// Use different color scheme
styles.Levels[velo.DebugLevel] = lipgloss.NewStyle().
    SetString("DEBG").
    Bold(true).
    Foreground(lipgloss.Color("33"))  // Bright blue

styles.Levels[velo.InfoLevel] = lipgloss.NewStyle().
    SetString("INFO").
    Bold(true).
    Foreground(lipgloss.Color("82"))  // Bright green

styles.Levels[velo.WarnLevel] = lipgloss.NewStyle().
    SetString("WARN").
    Bold(true).
    Foreground(lipgloss.Color("214")) // Orange

styles.Levels[velo.ErrorLevel] = lipgloss.NewStyle().
    SetString("ERRO").
    Bold(true).
    Foreground(lipgloss.Color("196")) // Bright red

velo.SetDefaultStyles(styles)

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Custom Field Key Styling

styles := velo.DefaultStyles()

// Highlight specific keys
styles.Keys["error"] = lipgloss.NewStyle().
    Foreground(lipgloss.Color("196")).
    Bold(true)

styles.Keys["user_id"] = lipgloss.NewStyle().
    Foreground(lipgloss.Color("45"))

styles.Keys["duration"] = lipgloss.NewStyle().
    Foreground(lipgloss.Color("214"))

velo.SetDefaultStyles(styles)

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Minimalist Theme

styles := velo.DefaultStyles()

// Remove all colors and formatting
styles.Timestamp = lipgloss.NewStyle()
styles.Caller = lipgloss.NewStyle()
styles.Prefix = lipgloss.NewStyle()
styles.Message = lipgloss.NewStyle()
styles.Key = lipgloss.NewStyle()
styles.Value = lipgloss.NewStyle()
styles.Separator = lipgloss.NewStyle()

// Simple level indicators
for level := range styles.Levels {
    styles.Levels[level] = lipgloss.NewStyle().
        SetString(strings.ToUpper(level.String()))
}

velo.SetDefaultStyles(styles)

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High Contrast Theme

styles := velo.DefaultStyles()

// High contrast colors for accessibility
styles.Message = styles.Message.
    Foreground(lipgloss.Color("255")). // Bright white
    Bold(true)

styles.Key = styles.Key.
    Foreground(lipgloss.Color("51"))   // Cyan

styles.Value = styles.Value.
    Foreground(lipgloss.Color("226"))  // Yellow

velo.SetDefaultStyles(styles)

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Performance Considerations

The CachedLevelStrings map stores pre-rendered level strings to avoid re-rendering on every log entry. This is automatically populated by DefaultStyles() and SetDefaultStyles().
When creating custom styles, ensure you populate CachedLevelStrings for optimal performance:
styles.CachedLevelStrings = make(map[Level]string)
for level, style := range styles.Levels {
    styles.CachedLevelStrings[level] = style.String()
}

TextFormatter

Learn about text formatting

Configuration

Configure logger output formats

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