Sunday, May 22, 2016

ES6 highlighting and lint checking in vim

I am a long-time "vimmie" (that is, I use vim for my IDE) and I love the plugin ecosystem which lets me do just about anything I want.

For example, I recently started using ReactJS (wish I hadn't wasted to so much time trying to get Angular to work) and one thing I love about it is how straight-forward it is to setup and start writing TDD/BDD for development (but that's another story).  My configuration uses Babel and es6, so I wanted to get syntax checking and indentation/highlighting working right off the bat.

Here's how -- it's pretty easy. I'm using Vundle as my plugin manager so that's the examples given. If you're using pathogen or vim-plug as your plugin manager, it should be pretty easy to modify and get it running. I've used pathogen and it's excellent, but have no experience with vim-plug.

  1. If this is the first time you've used a plugin, go to the Vundle website and follow the instructions there.
  2. Install the vim-javascript plugin by pangloss: vim-pangloss. This will give you basic syntax-highlighting / indentation using vim's built-in syntax support.
  3. Install the syntastic plugin by scrooloose: syntastic (he's the author of the excellent NERDTree plugin which gives you a hierarchical tree menu for system files). This will allow you to use external syntax checkers with vim, in addition to the built-in syntax checking already available. I use the eslint program for this. The options I use in vim for syntastic are:
    """"""""""""""""""""" Syntastic """"""""""""""""""""""""
    " From:
    set statusline+=%#warningmsg#
    set statusline+=%{SyntasticStatuslineFlag()}
    set statusline+=%*
    let g:syntastic_always_populate_loc_list = 1
    let g:syntastic_loc_list_height = 5
    let g:syntastic_auto_loc_list = 0
    let g:syntastic_check_on_open = 1
    let g:syntastic_check_on_wq = 1
    let g:syntastic_javascript_checkers = ['eslint']
    let g:syntastic_error_symbol = '❌'
    let g:syntastic_style_error_symbol = '⁉️'
    let g:syntastic_warning_symbol = '⚠️'
    let g:syntastic_style_warning_symbol = '💩'
    highlight link SyntasticErrorSign SignColumn
    highlight link SyntasticWarningSign SignColumn
    highlight link SyntasticStyleErrorSign SignColumn
    highlight link SyntasticStyleWarningSign SignColumn
  4. Install the eslint program. This is a node module installed with the 'global' option so that it's available everywhere as an executable. This is just
    npm install -g eslint
  5. You would think this would work (I sure did) but it's not yet fully baked. With this setup, the first import statement in some of your .js files will be flagged as an error. To solve this issue, you have to give eslint a few parameters, in the file ~/.eslintrc.json
    // From:
        "parserOptions": {
            "ecmaVersion": 6,
            "sourceType": "module",
            "ecmaFeatures": {
                "jsx": true
        "rules": {
            "semi": 2
Now you've got full es6 syntax checking and error notifications.

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