Neovim remote JS

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# Neovim remote JS

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# Neovim + Node = ♥

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# Neovim ⇄ Node
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## Communication?
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## Socket!

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# MsgPack
http://msgpack.org

« It's like JSON, but fast and small »

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# MsgPack5 JS

https://github.com/mcollina/msgpack5

- decode
- encode

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#MsgPack5-RPC JS

https://github.com/tarruda/node-msgpack5rpc

```javascript
const Session = require('msgpack5rpc')
const session = new Session()

session.attach(process.stdout, process.stdin)
session.on('request', (method, args, resp) => {
  resp.send('response!')
  console.log('received request')
  session.request('remote-method', ['arg1', 'arg2'], (err, res) => {
    console.log('received response')
  })
})
session.on('notification', (method, args) => {
  console.log('received notification')
  session.notify('remote-event', ['arg1', 'arg2'])
})
```

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# Node-Client
### attach

https://github.com/neovim/node-client

```javascript
const cp = require('child_process')
const attach = require('neovim-client')
const nvimProc = cp.spawn('nvim', ['-u', 'NONE', '-N', '--embed'], {})

attach(nvimProc.stdin, nvimProc.stdout, (err, nvim) => {

// …

})
```

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# Node-Client
### request and notif events

```javascript
attach(nvimProc.stdin, nvimProc.stdout, (err, nvim) => {

nvim.on('request', (method, args, resp) => {
    // handle msgpack-rpc request
  })

nvim.on('notification', (method, args) => {
    // handle msgpack-rpc notification
  })

})
```

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# Node-Client
### command

```javascript
attach(nvimProc.stdin, nvimProc.stdout, (err, nvim) => {
  nvim.command('vsp', (err, res) => {
    nvim.getWindows((err, windows) => {
      console.log(windows.length)  // 2
      console.log(windows[0] instanceof nvim.Window) // true
      nvim.setCurrentWindow(windows[1], (err, res) => {
        nvim.getCurrentWindow((err, win) => {
          console.log(win.equals(windows[1]))  // true
          nvim.quit()
          nvim.on('disconnect', () => {
            console.log("Nvim exited!")
          })
        })
      })
    })
  })
})
```

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# Callback hell

![hell](images/hell.gif)

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# Node-Client

```javascript
let attach = require('neovim-client/promise')
let nvim

attach(nvimProc.stdin, nvimProc.stdout)
.then((_nvim) => {
  nvim = _nvim
  return nvim.command('vsp')
})
.then((res) => nvim.getWindows())
.then((windows) => {
  console.log(windows.length)  // 2
  console.log(windows[0] instanceof nvim.Window) // true

// …
})
```

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# API
### created at runtime

```javascript
session.request('vim_get_api_info', [], (err, res) => {
  // read metadata and dynamically build 
  // Tabpage, Window and Buffer
  // and their associated methods
})
```

### :h api

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# NyaoVim
https://github.com/rhysd/NyaoVim

**react** component in an **electron** using **node-client**

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# Mmm…OK…

### What about going back to Neovim?

![confused](images/confused.gif)

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# Plugins!

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# Node-Host
https://github.com/neovim/node-host

- Install (with vim-plug):

```
if has('nvim')
  Plug 'neovim/node-host'
endif
```

- Then put your JS files in:

`$XDG_CONFIG_HOME/nvim/rplugin/node`

- Finally, register them with:

`:UpdateRemotePlugins`

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# Node-Host
### command

```javascript
plugin.commandSync('DanseLeMia', {
  range: '',
  nargs: '*',
}, (nvim, args, range, cb) => {
  nvim.setCurrentLine('Chemise ouverte, chaîne en or qui brille', cb)
})
```

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# Node-Host
### autocmd

```javascript
plugin.autocmdSync('BufEnter', {
  pattern: '*.xml',
  eval: 'expand("<afile>")'
}, (nvim, filename, cb) => {
  nvim.setCurrentLine('YOLO', cb)
})
```

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# Node-Host
### function

```javascript
plugin.function('SplitInThirteen', (nvim, args) => {
  nvim.setCurrentLine('1 1 1 1 1 1 1 1 1 1 1 1 1')
})
```

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# magic

![magic](images/magic.gif)

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# Node-Host

- it scans the `rplugin/node` directory
- it rewraps the found CommonJS modules in a sandbox
- it injects a new `plugin` *global*
- it uses Node-Client under the hood

all of that in JS of course!

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# Recap

- MsgPack5
- MsgPack5-RPC
- Node-Client
- Node-Host

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# Example

```javascript
const five = require('five')

Object.keys(five).forEach(k => {
  plugin.commandSync(`Five${k}`, {
    range: '',
    nargs: '*'
  },
  (nvim, args, range, cb) => {
    try {
      nvim.setCurrentLine(five[k](), cb)
    } catch (ex) {
      cb(ex)
    }
  })
})
```

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# :q