vue-command

A fully working, most feature-rich Vue.js terminal emulator. See the demo and check the demo source code.

Features

• Parses arguments with getopts
• Supports asynchronous commands
• Browse history (with ↑/↓)
• Autocompletion resolver (with ↹)
• Customize terminal with slots
• Search history (with Ctrl + r)

Installation

$ npm install vue-command --save

Usage

Let's start with a very simple example. We want to send "Hello world" to Stdout when entering hello-world.

<template>
  <vue-command :commands="commands" />
</template>

<script>
import VueCommand, { createStdout } from 'vue-command'
import 'vue-command/dist/vue-command.css'

export default {
  components: {
    VueCommand
  },

  data: () =>  ({
    commands: { 
      'hello-world': () => createStdout('Hello world') 
    }
  })
}
</script>

Now a more complex one. Let's assume we want to build the Nano editor available in many shells.

We will use the provided environment variable to make sure the editor is only visible when this command is executing and inject a function called terminate to tell the terminal that the command has been finished when the user enters Ctrl + x. Furthermore, we inject the setIsFullscreen function to switch the terminal into fullscreen mode.

<template>
  <div v-if="environment.isExecuting">
    <textarea
      ref="nano"
      @keydown.ctrl.88="terminate">This is a text editor! Press Ctrl + x to leave.</textarea>
  </div>
</template>

<script>
export default {
  inject: ['setIsFullscreen', 'terminate'],

  created () {
    this.setIsFullscreen(true)
  },

  mounted () {
    this.$refs.nano.focus()
  }
}
</script>

Now the command has to return the component.

<template>
  <vue-command :commands="commands" />
</template>

<script>
import VueCommand from 'vue-command'
import 'vue-command/dist/vue-command.css'

import NanoEditor from '@/components/NanoEditor.vue'

export default {
  components: {
    VueCommand
  },

  data: () =>  ({
    commands: { 
      nano: () => NanoEditor 
    }
  })
}
</script>

Properties

There are two types of commands: Built-in and regular ones. In most cases regular commands are appropriate. Built-in commands provide higher flexibility, see section Built-in for more information.

Some properties can be changed by the terminal, therefore, the sync modifier has to be added.

Commands

commands must be an object containing key-value pairs where key is the command and the value is a function that will be called with the getops arguments. The function can return a Promise and must return or resolve a Vue.js component. To return strings or nothing use one of the convenient helper methods:

Helper methods can be imported by name:

import { createStdout, createStderr, createDummyStdout } from 'vue-command'

If none of the helper methods is used, the command has to be manually terminated inside the component. Next to termination it's possible to inject the following functions to manipulate the terminal or signal an event:

Functions can be injected into your component by name:

inject: ['setIsFullscreen', 'setIsInProgress', 'terminate']

In your component you have access to a context and an environment variable. The environment variable contains the following properties (note that built-in commands have to take care by theirselves about the terminals state):

The context variable contains the following properties:

Built-in

Built-in commands provide more control over the terminals behaviour. On the other side, they have to take care about every regular command step. As a matter of fact, regular commands are just calling helper methods or change properties which could be also called or changed by built-in commands. Regular commands can be seen as a facade to built-in commands.

Since built-in commands can capture any command, it's necessary to take care of autocompletion and the command not found experience.

The first argument that is called within the built-in command is the unparsed Stdin. It's possible to use a custom parser at this place. The second argument is the terminal instance. You can use the commandNotFound method if no built-in or regular command has been found.

To fully simulate a regular command circle a built-in command has to follow these steps:

1. Call setIsInProgress with true to tell there is a command in progress
2. Add the programm to the executed Set property
3. Increase the history pointer with setPointer
4. Execute actual task
5. Push the Stdout component into the history property
6. Call setIsInProgress with false to tell there is no command in progress anymore

Autocompletion resolver

It is possible to provide a function that is called when the user hits the ↹ key. This function needs to take care of the autocompletion experience and should make usage of properties like history and stdin. The following shows a possible, simple autocompletion function:

this.autocompletionResolver = () => {
  // Make sure only programs are autocompleted. See below for version with options
  const command = this.stdin.split(' ')
  if (command.length > 1) {
    return
  }

  const autocompleteableProgram = command[0]
  // Collect all autocompletion candidates
  let candidates = []
  const programs = [...Object.keys(this.commands)].sort()
  programs.forEach(program => {
    if (program.startsWith(autocompleteableProgram)) {
      candidates.push(program)
    }
  })

  // Autocompletion resolved into multiple results
  if (this.stdin !== '' && candidates.length > 1) {
    this.history.push({
      // Build table programmatically
      render: createElement => {
        const columns = candidates.length < 5 ? candidates.length : 4
        const rows = candidates.length < 5 ? 1 : Math.ceil(candidates.length / columns)

        let index = 0
        let table = []
        for (let i = 0; i < rows; i++) {
          let row = []
          for (let j = 0; j < columns; j++) {
            row.push(createElement('td', candidates[index]))
            index++
          }

          table.push(createElement('tr', [row]))
        }

        return createElement('table', { style: { width: '100%' } }, [table])
      }
    })
  }

  // Autocompletion resolved into one result
  if (candidates.length === 1) {
    this.stdin = candidates[0]
  }
}

this.autocompletionResolver = () => {
  // Preserve cursor position
  const cursor = this.cursor

  // Reverse concatenate autocompletable according to cursor
  let pointer = this.cursor
  let autocompleteableStdin = ''
  while (this.stdin[pointer - 1] !== ' ' && pointer - 1 > 0) {
    pointer--
    autocompleteableStdin = `${this.stdin[pointer]}${autocompleteableStdin}`
  }

  // Divide by arguments
  const command = this.stdin.split(' ')

  // Autocompleteable is program
  if (command.length === 1) {
    const autocompleteableProgram = command[0]
    // Collect all autocompletion candidates
    const candidates = []
    const programs = [...Object.keys(this.commands)].sort()
    programs.forEach(program => {
      if (program.startsWith(autocompleteableProgram)) {
        candidates.push(program)
      }
    })

    // Autocompletion resolved into multiple results
    if (this.stdin !== '' && candidates.length > 1) {
      this.history.push({
        // Build table programmatically
        render: createElement => {
          const columns = candidates.length < 5 ? candidates.length : 4
          const rows = candidates.length < 5 ? 1 : Math.ceil(candidates.length / columns)

          let index = 0
          const table = []
          for (let i = 0; i < rows; i++) {
            const row = []
            for (let j = 0; j < columns; j++) {
              row.push(createElement('td', candidates[index]))
              index++
            }

            table.push(createElement('tr', [row]))
          }

          return createElement('table', { style: { width: '100%' } }, [table])
        }
      })
    }

    // Autocompletion resolved into one result
    if (candidates.length === 1) {
      // Mutating Stdin mutates the cursor, so we've to wait to push it to the end
      const unwatch = this.$watch(() => this.cursor, () => {
        this.cursor = cursor + (candidates[0].length - autocompleteableStdin.length + 0)

        unwatch()
      })

      this.stdin = candidates[0]
    }

    return
  }

  // Check if option might be completed already or option is last tokens
  if ((this.stdin[cursor] !== '' && this.stdin[cursor] !== ' ') && typeof this.stdin[cursor] !== 'undefined') {
    return
  }

  // Get the executable
  const program = command[0]

  // Check if any autocompleteable exists
  if (typeof this.options.long[program] === 'undefined' && typeof this.options.short[program] === 'undefined') {
    return
  }

  // Autocompleteable is long option
  if (autocompleteableStdin.substring(0, 2) === '--') {
    const candidates = []
    this.options.long[program].forEach(option => {
      // If only dashes are present, user requests all options
      if (`--${option}`.startsWith(autocompleteableStdin) || autocompleteableStdin === '--') {
        candidates.push(option)
      }
    })

    // Autocompletion resolved into one result
    if (candidates.length === 1) {
      const autocompleted = `${this.stdin.substring(0, pointer - 1)} --${candidates[0]}`
      const rest = `${this.stdin.substring(this.cursor)}`

      // Mutating Stdin mutates the cursor, so we've to wait to push it to the end
      const unwatch = this.$watch(() => this.cursor, () => {
        this.cursor = cursor + (candidates[0].length - autocompleteableStdin.length + 2)

        unwatch()
      })

      this.stdin = `${autocompleted}${rest}`

      return
    }

    // Autocompletion resolved into multiple result
    if (autocompleteableStdin === '--' || candidates.length > 1) {
      this.history.push({
        // Build table programmatically
        render: createElement => {
          const columns = candidates.length < 5 ? candidates.length : 4
          const rows = candidates.length < 5 ? 1 : Math.ceil(candidates.length / columns)

          let index = 0
          const table = []
          for (let i = 0; i < rows; i++) {
            const row = []
            for (let j = 0; j < columns; j++) {
              row.push(createElement('td', `--${candidates[index]}`))
              index++
            }

            table.push(createElement('tr', [row]))
          }

          return createElement('table', { style: { width: '100%' } }, [table])
        }
      })
    }

    return
  }

  // Autocompleteable is option
  if (autocompleteableStdin.substring(0, 1) === '-') {
    const candidates = []
    this.options.short[program].forEach(option => {
      // If only one dash is present, user requests all options
      if (`-${option}`.startsWith(autocompleteableStdin) || autocompleteableStdin === '-') {
        candidates.push(option)
      }
    })

    // Autocompletion resolved into one result
    if (candidates.length === 1) {
      const autocompleted = `${this.stdin.substring(0, pointer - 1)} -${candidates[0]}`
      const rest = `${this.stdin.substring(this.cursor)}`

      // Mutating Stdin mutates the cursor, so we've to wait to push it to the end
      const unwatch = this.$watch(() => this.cursor, () => {
        this.cursor = cursor + (candidates[0].length - autocompleteableStdin.length + 1)

        unwatch()
      })

      this.stdin = `${autocompleted}${rest}`

      return
    }

    // Autocompletion resolved into multiple result
    if (autocompleteableStdin === '-' || candidates.length > 1) {
      this.history.push({
        // Build table programmatically
        render: createElement => {
          const columns = candidates.length < 5 ? candidates.length : 4
          const rows = candidates.length < 5 ? 1 : Math.ceil(candidates.length / columns)

          let index = 0
          const table = []
          for (let i = 0; i < rows; i++) {
            const row = []
            for (let j = 0; j < columns; j++) {
              row.push(createElement('td', `-${candidates[index]}`))
              index++
            }

            table.push(createElement('tr', [row]))
          }

          return createElement('table', { style: { width: '100%' } }, [table])
        }
      })
    }
  }
}

Event listeners

Event listeners trigger terminal behaviour under certain conditions like pressing a button. Pass an array of event listeners you want to bind via the event-listeners property. This library provides three event listeners per default which can be imported:

• Autocompletion: Autocompletion when pressing ↹
• History: Cycle through history with ↑/↓
• Search: Search history with Ctrl and r

An event listener is called with the Vue.js component instance as argument.

Slots

Bar

It's possible to fully customize the terminal bar using slots as shown in the following. Note: If using the bar slot, the properties hide-bar and title will be ignored.

<template>
  <vue-command>
    <div slot="bar">
      Pokedex
    </div>
  </vue-command>
</template>

Prompt

Customize the prompt with the prompt slot. Note: If using the prompt slot, the property prompt will be ignored and the CSS class term-ps has to be manually applied.

<template>
  <vue-command prompt="neil">
    <span
      class="term-ps" 
      slot="prompt">
      {{ prompt }} ready to take off:
    </span>
  </vue-command>
</template>

Events

Browser support

This library uses the ResizeObserver to track if the terminals inner height changes. You may need a pollyfill to support your target browser.

Overwriting executed functions

To track when the executed property has been mutated, this library overwrites the functions add, clear and delete of it. That means if you plan to overwrite the named Set functions by yourself, this library won't work.

Projects using vue-command

• docker-management-dashboard - A management dashboard for your local docker containers
• saber-theme-klieh - A Saber theme mimicking a terminal
• ts-git - A naïve implementation of git, written in TypeScript
• curvy-idle-game - Short idle game where you get to pat her

Chuck Norris API

The Chuck Norris jokes are comming from this API. This library has no relation to Chuck Norris or the services provided by the API.

Author

Julian Claus and contributors. Special thanks to krmax44 for the amazing work!

I apologize to some contributors that are not in the Git history anymore since I had to delete the repository because of problems with semantic-release.

License

MIT