How to use the xPack Mock Console

This section is intended for those who plan to use this module in their own projects.

The @xpack/mock-console module can be imported into both TypeScript and JavaScript Node.js code.

In TypeScript and ECMAScript modules, use import:

import { MockConsole } from '@xpack/mock-console'

In JavaScript with CommonJS, use require():

const { MockConsole } = request('@xpack/mock-console')

The module can be included in any application and the class can be used directly or a custom class can be derived from it for a custom behaviour.

The typical use case is to create an instance of the Logger object, then log messages at different levels:

const mockConsole = new MockConsole()

const log = new Logger({
  console: mockConsole,
  level: 'info'
})

The logged lines are available in the outLines and errLines public members:

t.ok(mockConsole.outLines.length > 0, 'has stdout')
t.match(mockConsole.outLines[1], 'Multiple subcommands', 'has title')

t.equal(mockConsole.errLines.length, 0, 'stderr is empty')

For debug purposes, there is also a function that can be used to display string arrays with the lines prefixed by a line number; this is useful in tests to decide what lines to check:

import { dumpLines } from '@xpack/mock-console'

dumpLines(mockConsole.outLines)

Reference

For more details on the available class definitions, including all methods, accessors, properties, etc, please see the TypeDoc API pages.

Reference​

Reference