Spacemacs setup

Install emacs on your platform (apt on Ubuntu or the distro's app store, brew on MacOS (update: better to install from https://emacsformacosx.com/ since you'll get proper GUI support), download .exe from https://www.gnu.org/software/emacs/download.html for Windows). Install 32-bit version (at least if you are on Windows) as that seems to have better performance compared to the 64-bit version. I downloaded emacs-26.3-i686.zip for my Windows machine

Run the following commands:

rm -r ~/.emacs.d (make backup if you already have this folder)
git clone https://github.com/syl20bnr/spacemacs ~/.emacs.d

At the time of writing (Dec 2019), the released version of spacemacs is 0.200. Performance of this version seems a bit lacking. Start up time feels too long, files are slow to load sometimes, and cursor movement is also slow at times. Switching to develop branch seems to improve performance by quite a margin, and also enable the latest features. Of course, you run the risk of some stuff being broken, but it's been worth it for the performance gains, and I haven't yet encountered any critical bugs that broke my work flow.

cd ~/.emacs.d
git checkout develop

Run emacs now. On Windows, use the runemacs.exe instead of emacs.exe as the former doesn't spawn a terminal window. Spacemacs will run and install a bunch of things, and ask you some questions about the configuration you want. I went with the default ones.

Open ~/.spacemacs file and give it a read. It's very well documented, and was somewhat easy to get a basic understanding of the settings within.
You might want to configure font settings first. The default is set to "Source Code Pro" which may or may not be installed on your system. I changed mine to "Consolas" with :size 12. You might also want to change the :powerline-scale setting if your modeline/powerline (the bar at the bottom of your screen) has some rendering issues. (This doesn't seem necessary for 0.300)
Next, enable/add the layers that you need under the dotspacemacs-configuration-layers. Layers can be thought of a set of packages (plugins) that get enabled when in a particular major-mode, and that play well together. Some of the plugins may require certain applications to be installed before they can work properly (like tern or linters).
If you want to add a package without it being associated with a layer, you can add it under dotspacemacs-additional-packages. Packages that you don't want installed go under dotspacemacs-excluded-packages
Custom configuration goes under dotspacemacs/user-config. Here's mine at the time of writing:

(defun dotspacemacs/user-config ()
  (evil-select-search-module 'evil-search-module 'evil-search)
  (setq hybrid-mode-enable-hjkl-bindings t)
  (setq dotspacemacs-mode-line-unicode-symbols nil)
  (setq scroll-margin 10)
  (setq helm-ag-base-command "c:/ProgramData/chocolatey/bin/ag.exe --vimgrep")
  (setq js-indent-level 2)
  (add-hook 'org-mode-hook 'spacemacs/toggle-truncate-lines-off)
  (add-hook 'org-mode-hook 'spacemacs/toggle-visual-line-navigation-on))

Here's a brief explanation of the settings above:

• evil-select-search-module makes search behave more like vim's rather than emacs. gn command wan't working quite correctly without this setting.
  
• hybrid-mode-enable-hjkl-bindings I'm not quite sure what this does. It's supposed to enable hjkl bindings outside of the main editor buffer as well, but I don't know exactly. I've set it to true, cause one can never have enough hjkl bindings I guess.
  
• dotspacemacs-mode-line-unicode-symbols Enables/disables unicode symbols in the modeline. I disabled it cause they were looking ugly on Windows anyway. Someone on the internet also mentioned it might improve performance, but I couldn't really tell much difference.
  
• scroll-margin This setting is similar to vim's scrolloff setting.
  
• helm-ag-base-command Path to the installed Silver Searcher command. Silver searcher is better than the default grep search when searching for files or occurrences within a project cause ag respects your .gitignore file and doesn't clutter your search results with results from unnecessary sources (such as node_modules). Remember to add the --vimgrep flag or it won't work correctly. This step isn't necessary on Mac and Unix. (Update: I'm using ripgrep instead of ag now, and if you are running 0.300 of Spacemacs, you only need to ensure that ripgrep is in your $PATH, and this step is not required).
  
• js-indent-level This sets the indentation level (shiftwidth). I'm still not sure about how to correctly configure tabstops and indentation levels in emacs yet, but from what I could gather it seems like indentation is controlled by different variables depending on the major mode, which is quite a bummer. js-indent-level controls the indentation for js files
  
• add-hook commands are somewhat similar to autocmd in vim, and is used to set major-mode specific settings. Here I'm setting line-wrapping and making jk keys traverse visual lines instead of actual lines.
  

Setting a new theme in spacemacs is really simple. Visit https://themegallery.robdor.com/ and choose a theme that you like. Then add the theme to dotspacemacs-themes or replace an existing one. Here's what mine looks like: dotspacemacs-themes '(ujelly spacemacs-dark). The themes can be cycled through by using SPC T n
There's a layer called themes-megapack, but I would caution against using that as it seemed to mess with my .spacemacs configuration by adding a bunch of things under custom-set-variables, but I couldn't figure out what exactly and ended up resetting my .spacemacs file.

Check the https://github.com/emacs-lsp/lsp-mode link for various LSP servers. For javascript/typescript, the LSP server requires node to run. If you use nvm to manage your node instances, chances are that the node executable won't be found. You can verify this by running eshell command and typing node. If it says "Command not found", then your LSP server won't run. This happens because nvm alters the $PATH variable when running .bashrc, which isn't run when launching eshell. Altering the exec-path variable to add path to node binary didn't help me in this case. I found it easiest to create a symlink to node under /usr/local/bin. Any globally installed node package that you expect to use from within emacs will need a symlink under /usr/local/bin.

sudo ln -s ~/.nvm/versions/node/v12.13.1/bin/node /usr/local/bin/node

Install the following external tools when setting up a new system:

• git
  
• nvm and node (create symlink to node under /usr/local/bin)
  
• ripgrep
  
• broot
  
• fzf
  
• diff so fancy
  
• rupa/z
  
• fd