command-line-usage

A simple, data-driven module for creating a usage guide.

Synopsis

A usage guide is created by first defining an arbitrary number of sections, e.g. a description section, synopsis, option list, examples, footer etc. Each section has an optional header, some content and must be of type content or optionList. This section data is passed to commandLineUsage() which returns a usage guide.

Inline ansi formatting can be used anywhere within section content using chalk template literal syntax.

For example, this script:

const commandLineUsage = require('command-line-usage')

const sections = [
  {
    header: 'A typical app',
    content: 'Generates something {italic very} important.'
  },
  {
    header: 'Options',
    optionList: [
      {
        name: 'input',
        typeLabel: '{underline file}',
        description: 'The input to process.'
      },
      {
        name: 'help',
        description: 'Print this usage guide.'
      }
    ]
  }
]
const usage = commandLineUsage(sections)
console.log(usage)

Outputs this guide:

More examples

Simple

A fairly typical usage guide with three sections - description, option list and footer. Code.

Option List groups

Demonstrates breaking the option list up into groups. Code.

Banners

A banner is created by adding the raw: true property to your content. This flag disables any formatting on the content, displaying it raw as supplied.

Header

Demonstrates a banner at the top. This example also adds a synopsis section. Code.

Footer

Demonstrates a footer banner. Code.

Examples section (table layout)

An examples section is added. To achieve this table layout, supply the content as an array of objects. The property names of each object are not important, so long as they are consistent throughout the array. Code.

Advanced optionList layout

The optionList layout is fully configurable by setting the tableOptions property with an options object suitable for passing into table-layout. This example overrides the default column widths and adds flame padding. Code.

Command list

Useful if your app is command-driven, like git or npm. Code.

Description section (table layout)

Demonstrates supplying specific table layout options to achieve more advanced layout. In this case the second column (containing the hammer and sickle) has a fixed width of 40 and noWrap enabled (as the input is already formatted as desired). Code.

Whitespace

By default, whitespace from the beginning of each line is trimmed to ensure wrapped text always aligns neatly to the left edge of the column. This can be undesirable when whitespace is intentional like the indented bullet points shown in this example. The two ways to disable whitespace trimming are shown in this example code.

Real-life

The polymer-cli usage guide is a good real-life example.

API Reference

command-line-usage
- commandLineUsage(sections) ⇒ string ⏏
  - ~content
  - ~optionList

commandLineUsage(sections) ⇒ `string` ⏏

Generates a usage guide suitable for a command-line app.

Kind: Exported function

Param	Type	Description
sections	`Section` \| `Array.<Section>`	One or more section objects (content or optionList).

commandLineUsage~content

A Content section comprises a header and one or more lines of content.

Kind: inner typedef of commandLineUsage
Properties

Name Type Description

header

Name	Type	Description
header	`string`	The section header, always bold and underlined.
content	`string` \| `Array.<string>` \| `Array.<object>`	Overloaded property, accepting data in one of four formats: A single string (one line of text) An array of strings (multiple lines of text) An array of objects (recordset-style data). In this case, the data will be rendered in table format. The property names of each object are not important, so long as they are consistent throughout the array. An object with two properties - `data` and `options`. In this case, the data and options will be passed directly to the underlying table layout module for rendering.
raw	`boolean`	Set to true to avoid indentation and wrapping. Useful for banners.

string

The section header, always bold and underlined.

content

string | Array.<string> | Array.<object>

Overloaded property, accepting data in one of four formats:

A single string (one line of text)
An array of strings (multiple lines of text)
An array of objects (recordset-style data). In this case, the data will be rendered in table format. The property names of each object are not important, so long as they are consistent throughout the array.
An object with two properties - data and options. In this case, the data and options will be passed directly to the underlying table layout module for rendering.

raw

boolean

Set to true to avoid indentation and wrapping. Useful for banners.

Example
Simple string of content. For ansi formatting, use chalk template literal syntax.

{
  header: 'A typical app',
  content: 'Generates something {rgb(255,200,0).italic very {underline.bgRed important}}.'
}

An array of strings is interpreted as lines, to be joined by the system newline character.

{
  header: 'A typical app',
  content: [
    'First line.',
    'Second line.'
  ]
}

An array of recordset-style objects are rendered in table layout.

{
  header: 'A typical app',
  content: [
    { colA: 'First row, first column.', colB: 'First row, second column.'},
    { colA: 'Second row, first column.', colB: 'Second row, second column.'}
  ]
}

An object with data and options properties will be passed directly to the underlying table layout module for rendering.

{
  header: 'A typical app',
  content: {
    data: [
     { colA: 'First row, first column.', colB: 'First row, second column.'},
     { colA: 'Second row, first column.', colB: 'Second row, second column.'}
    ],
    options: {
      maxWidth: 60
    }
  }
}

commandLineUsage~optionList

An OptionList section adds a table displaying the supplied option definitions.