docusaurus/packages/docusaurus-logger

@docusaurus/logger

An encapsulated logger for semantically formatting console messages.

APIs

It exports a single object as default export: logger. logger has the following properties:

• Some useful colors.
• Formatters. These functions have the same signature as the formatters of picocolors. Note that their implementations are not guaranteed. You should only care about their semantics.
  • path: formats a file path or URL.
  • id: formats an identifier.
  • code: formats a code snippet.
  • subdue: subdues the text.
  • num: formats a number.
• The interpolate function. It is a template literal tag.
• Logging functions. All logging functions can both be used as functions (in which it has the same usage as console.log) or template literal tags.
  • info: prints information.
  • warn: prints a warning that should be payed attention to.
  • error: prints an error (not necessarily halting the program) that signals significant problems.
  • success: prints a success message.

Using the template literal tag

The template literal tag evaluates the template and expressions embedded. interpolate returns a new string, while other logging functions prints it. Below is a typical usage:

logger.info`Hello name=${name}! You have number=${money} dollars. Here are the ${
  items.length > 1 ? 'items' : 'item'
} on the shelf: ${items}
To buy anything, enter code=${'buy x'} where code=${'x'} is the item's name; to quit, press code=${'Ctrl + C'}.`;

An embedded expression is optionally preceded by a flag in the form %[a-z]+ (a percentage sign followed by a few lowercase letters). If it's not preceded by any flag, it's printed out as-is. Otherwise, it's formatted with one of the formatters:

• path=: path
• name=: id
• code=: code
• subdue=: subdue
• number=: num

If the expression is an array, it's formatted by `\n- ${array.join('\n- ')}\n` (note it automatically gets a leading line end). Each member is formatted by itself and the bullet is not formatted. So you would see the above message printed as: