key-remapping-hammerspoon

Step 1

Download Hammerspoon from official github site

Unzip it and turn on permissions including Accessibility (this is important otherwise your eventtab will be failed to load)

Step 2

Create a Hammerspoon init file by doing this in your terminal

vi ~/.hammerspoon/init.lua

in which you can put your key remap configs. Since I wanted to remap my arrow keys so I added the following code to init.lua. The code is same as here

local function pressFn(mods, key)
	if key == nil then
		key = mods
		mods = {}
	end

	return function() hs.eventtap.keyStroke(mods, key, 1000) end
end

local function remap(mods, key, pressFn)
	hs.hotkey.bind(mods, key, pressFn, nil, pressFn)	
end


remap({"ctrl"}, "j", pressFn("left"))
remap({"ctrl"}, "k", pressFn("down"))
remap({"ctrl"}, "i", pressFn("up"))
remap({"ctrl"}, "l", pressFn("right"))

remap({"ctrl", "shift"}, "j", pressFn({"shift"}, "left"))
remap({"ctrl", "shift"}, "k", pressFn({"shift"}, "down"))
remap({"ctrl", "shift"}, "i", pressFn({"shift"}, "up"))
remap({"ctrl", "shift"}, "l", pressFn({"shift"}, "right"))

remap({"ctrl", "cmd"}, "j", pressFn({"cmd"}, "left"))
remap({"ctrl", "cmd"}, "k", pressFn({"cmd"}, "down"))
remap({"ctrl", "cmd"}, "i", pressFn({"cmd"}, "up"))
remap({"ctrl", "cmd"}, "l", pressFn({"cmd"}, "right"))

remap({"ctrl", "alt"}, "j", pressFn({"alt"}, "left"))
remap({"ctrl", "alt"}, "k", pressFn({"alt"}, "down"))
remap({"ctrl", "alt"}, "i", pressFn({"alt"}, "up"))
remap({"ctrl", "alt"}, "l", pressFn({"alt"}, "right"))

remap({"ctrl", "shift", "cmd"}, "j", pressFn({"shift", "cmd"}, "left"))
remap({"ctrl", "shift", "cmd"}, "k", pressFn({"shift", "cmd"}, "down"))
remap({"ctrl", "shift", "cmd"}, "i", pressFn({"shift", "cmd"}, "up"))
remap({"ctrl", "shift", "cmd"}, "l", pressFn({"shift", "cmd"}, "right"))

remap({"ctrl", "shift", "alt"}, "j", pressFn({"shift", "alt"}, "left"))
remap({"ctrl", "shift", "alt"}, "k", pressFn({"shift", "alt"}, "down"))
remap({"ctrl", "shift", "alt"}, "i", pressFn({"shift", "alt"}, "up"))
remap({"ctrl", "shift", "alt"}, "l", pressFn({"shift", "alt"}, "right"))

remap({"ctrl", "cmd", "alt"}, "j", pressFn({"cmd", "alt"}, "left"))
remap({"ctrl", "cmd", "alt"}, "k", pressFn({"cmd", "alt"}, "down"))
remap({"ctrl", "cmd", "alt"}, "i", pressFn({"cmd", "alt"}, "up"))
remap({"ctrl", "cmd", "alt"}, "l", pressFn({"cmd", "alt"}, "right"))

remap({"ctrl", "cmd", "alt", "shift"}, "j", pressFn({"cmd", "alt", "shift"}, "left"))
remap({"ctrl", "cmd", "alt", "shift"}, "k", pressFn({"cmd", "alt", "shift"}, "down"))
remap({"ctrl", "cmd", "alt", "shift"}, "i", pressFn({"cmd", "alt", "shift"}, "up"))
remap({"ctrl", "cmd", "alt", "shift"}, "l", pressFn({"cmd", "alt", "shift"}, "right"))

This will map

CTRL+i => up

CTRL+k => down

CTRL+j => left

CTRL+l => right

and also the more complex ones (I am sure you understand the rest of the code)

Step 3

You can reload the config by clock the Reload config in the Hammerspoon Console, this will reload the configurations in init.lua.

Step 4

Verification. Hope it works!