bnash/examples/custom-keys.js

A command-line editor for bash or compatible shells, aiming to provide great UX and productivity

/* This example plugin illustrates key binding API. When the editor is reading
    user input and some key combination is pressed, it checks for a registered
    function to handle the keyboard shortcut.

    This plugin registers 4 shortcut handlers:
    - The deleteWordToLeft shortcut handler is a simple, synchronous function
        that just updates the line being edited
    - The cdParent and cdBack shortcut handlers are asynchronous functions
        that execute commands (illustrating the runCommand API) and
        navigate the directory history (illustrating the history API).
    - The meta-h (alt-h) shortcut handler illustrates how to use the key binding
        API to reassign an existing shortcut handler to a different key
        combination.
*/

const { bindKey, getKeyBindingByFunction } = require(NASH_BASE + '/key-bindings')
const { runCommand } = require(NASH_BASE + '/runner')
const env = require(NASH_BASE + '/env')
const { dirHistory } = require(NASH_BASE + '/history')


function deleteWordToLeft(line) {
    return {
        left: line.left.replace(/\w+[^\w]*$/, ''),
        right: line.right
    }
}

async function cdParent(line) {
    if (env.cwd() == '/')
        return { ...line, showPrompt: false }
    await runCommand('cd ..')
    return { left: line.left, right: line.right }
}

async function cdBack(line) {
    let dir = dirHistory.back()
    if (dir == env.cwd())
        dir = dirHistory.back()
    if (!dir)
        return { ...line, showPrompt: false }
    await runCommand('cd ' +  dir, { pushDir: false })
    return { left: line.left, right: line.right }
}


function start() {
    // Register 'alt-backspace' key handler
    bindKey('meta-backspace', deleteWordToLeft,
        'Deletes the word before the cursor')

    // Register 'shift-up' key handler
    bindKey('shift-up', cdParent, 'Changes to the parent directory')
    // Register 'shift-down' key handler
    bindKey('shift-down', cdBack, 'Moves one directory back in history')

    // Get the key handler identified by 'listKeys' and re-assign it to 'alt-h'
    let help = getKeyBindingByFunction('listKeys')
    if (help)
        bindKey('meta-h', help.code, help.desc)
}


module.exports = { start }