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Logging Helpers

Handlebars provides a set of built-in helpers for logging and debugging. These helpers output messages to the terminal with various formatting and color options, making it easier to debug templates and display status information. Node.js only.

logging

Note: These helpers are only available in Node.js environments. They are not compatible with browser-based Handlebars usage.

These helpers output messages to the terminal with ANSI color formatting. All logging helpers return an empty string to avoid affecting template output.

{{log}}

Logs an unstyled message to the terminal via console.log.

Params

  • ...args {any}: Values to log
  • returns {String}: Empty string

Example

{{log "Processing item:" itemName}}

{{ok}}

Logs a green colored message preceded by a checkmark to the terminal. Useful for indicating successful operations.

Params

  • ...args {any}: Values to log (will be joined with spaces)
  • returns {String}: Empty string

Example

{{ok "Build completed successfully"}}

{{success}}

Logs a green colored message to the terminal. Similar to ok but without the checkmark.

Params

  • ...args {any}: Values to log (will be joined with spaces)
  • returns {String}: Empty string

Example

{{success "All tests passed"}}

{{info}}

Logs a cyan colored informational message to the terminal.

Params

  • ...args {any}: Values to log (will be joined with spaces)
  • returns {String}: Empty string

Example

{{info "Processing" totalCount "items"}}

{{warning}}

Logs a yellow colored warning message to stderr.

Params

  • ...args {any}: Values to log (will be joined with spaces)
  • returns {String}: Empty string

Example

{{warning "Deprecated feature detected"}}

{{warn}}

Alias for {{warning}}. Logs a yellow colored warning message to stderr.

Params

  • ...args {any}: Values to log (will be joined with spaces)
  • returns {String}: Empty string

Example

{{warn "This method will be removed in v5"}}

{{error}}

Logs a red colored error message to stderr.

Params

  • ...args {any}: Values to log (will be joined with spaces)
  • returns {String}: Empty string

Example

{{error "Failed to process item:" itemId}}

{{danger}}

Alias for {{error}}. Logs a red colored error message to stderr.

Params

  • ...args {any}: Values to log (will be joined with spaces)
  • returns {String}: Empty string

Example

{{danger "Critical failure in module"}}

{{bold}}

Logs a bold formatted message to stderr.

Params

  • ...args {any}: Values to log (will be joined with spaces)
  • returns {String}: Empty string

Example

{{bold "Important Notice"}}

{{_debug}}

Outputs debug information including the provided value and the current Handlebars context. Useful for inspecting template data during development.

Params

  • ...args {any}: Optional values to inspect
  • returns {String}: Empty string

Example

{{_debug user}}

{{_inspect}}

Formats a value as JSON and returns it for display in the template. Supports different output formats.

Params

  • context {any}: The value to inspect
  • options.hash.type {String}: Output format: "html" (default), "md", or any other value for raw JSON
  • returns {String}: Formatted JSON string

Example

{{_inspect user}}


{{_inspect user type="md"}}



{{_inspect user type="raw"}}