a command-line helper for Node.js

Usage no npm install needed!

<script type="module">
  import 8patternJcommand from 'https://cdn.skypack.dev/@8pattern/jcommand';



A command-line helper for Node.js


npm install -S @8pattern/jcommand



// cmd.js
const jCommand = require('@8pattern/jcommand')
jCommand.option(['-P', '--port'], (cmd) => console.log(cmd.value))
node cmd.js -P=3000 or node cmd.js --port=3000
# the console will print 3000 
  • Attribute

    1. execPath <string>: the path of the executor. It's Node root path in ordinary.

      node cmd.js
      # jCommand.execPath === 'D:\\Node\\node.exe'
    2. filePath <string>: the path of the code file.

      node cmd.js
      # jCommand.filePath === 'D:\\cmd.js'
    3. args <string[]>: the original arguments in command-line.

      node cmd.js -a -b=1 c:2
      # jCommand.args === ['-a', '-b=1', 'c:2']
    4. commands <Command[]> the list of argument wraps. Command is a wrapper for argument. It has five attributes: rawcommand, value, pre and next. raw represents the original string of the argument. command and value will be automatically detect the argument to obtain the corresponding results (according to "=" now). If they can't be detected from the raw, command will equal the raw while the value will be assigned to be null. pre and next link the previous or next argument wrap instance. For example:

      Argument -a -b=1 c:2
      raw -a -b=1 c:2
      command -a -b c:2
      value null 1 null
      node cmd.js -a -b=1 c:2
      # jCommand.commands[1].raw === '-b=1'
      # jCommand.commands[1].pre.raw === '-a'
      # jCommand.commands[1].next.raw === 'c:2'
  • Action

    1. option (command: string | string[], callback: Function): jCommand
    • exactly match the received commands
      jCommand.option('-P', callback)
      jCommand.option(['-P', '--port'], callback)
    1. match (command: RegExp, callback: Function): jCommands
    • provide a regular expression to match all valid argument

      jCommand.option(/--?P/i, callback)
    1. fuzzy (command: string | string[], callback: Function): jCommand or (command: string | string[], prefix: string | string[], callback: Function): jCommand

      • match the arguments in a case insensitive mode
      • the prefix argument represents the prefix chars before the argument, ['-', '--'] by default
      jCommand.fuzzy('p', callback) // sames as jCommand.fuzzy('p', ['-', '--'], callback)
      jCommand.fuzzy(['p', 'port'], '-', callback)
    2. valid (validator: Function, callback: Function): jCommand

      • can provide a custom validator to match the expected arguments.
      • validator can receive the only argument —— a Command instance. If return true, the command will be regarded as selected. And false otherwise.
      • In fact, option, match and fuzzy are three particular cases of valid.

    The following presents whether the arguments will trigger the corresponding rules.

    -p -P --p -p=3000 --port=3000
    option('-p', cb) Yes No No Yes No
    option(['-p', '--port'], cb) Yes No No Yes Yes
    match(/-p/, cb) Yes No Yes Yes Yes
    match(/--P/i, cb) No No Yes No Yes
    match(/^--?p$/i, cb) Yes Yes Yes Yes No
    fuzzy('p', cb) Yes Yes Yes Yes No
    fuzzy('p', '@', cb) No No No No No


    1. the actions can be called by chains.
    const t = jCommand
        .option('-p',() => {})
        .match(/w/, () => {})
      .fuzzy('m', () => {})
      .valud(() => true, () => {})
    console.log(t === jCommand) // true
    1. callback has the only argument of the Command instance. If need the previous or rest command-line arguments, they will can be found by pre and next attributes.
    jCommand.option('-P', (cmd) => {
    // node cmd.js -P 3000  -> print 3000
    1. only if the rule satisfied, the callback will be triggered, even if it was triggered before. In other words, the callback may be triggered more than once.
      .option('-P', (cmd) => console.log('option:', cmd.command))
      .match(/p/i, (cmd) => console.log('match: ', cmd.command))
      .fuzzy('p', (cmd) => console.log('fuzzy: ', cmd.command))
      .valid((cmd) => /p/i.test(cmd.command), (cmd) => console.log('valid: ', cmd.command))
    // node cms.js -P
    // print:
    //	option: -P
    //  match: -P
    //  fuzzy: -P
    //  valid: -P