[目的]
VimでEsc押下時に英数入力に変更する

[対象]
Terminal, iTerm2, Cloud9, MacVim

[環境]
OS X El Capitan 10.11.6

[手順]
１. Install Karabiner-Elements
Download From https://pqrs.org/osx/karabiner/
２. Create Setting_File
Launch Terminal or iTerm2
vi　~/.config/karabiner/assets/complex_modifications/FromEscapeToJapanese_eisuu.json

FromEscapeToJapanese_eisuu.json

{
  "title": "Terminal等でESC時に日本語入力を英数に",
  "rules": [
        {
  "description": "Terminal等でESCを押したときに日本語入力を英数に切り替える。",
  "manipulators": [
       {
        "type": "basic",
        "from": { "key_code": "escape", "modifiers": { "optional": [ "any" ] } },
        "to": [ { "key_code": "japanese_eisuu" }, { "key_code": "escape" } ],
        "conditions": [ { "type": "frontmost_application_if",
        "bundle_identifiers": [
          "^com\\.apple\\.Terminal$",
          "^org\\.vim\\.",
          "^com\\.googlecode\\.iterm2$",
          "^org\\.mozilla\\.firefox$",
          "^com\\.google\\.Chrome$",
          "^com\\.apple\\.Safari$"
       ]
      }
     ]
    }
   ]
  }
 ]
}

３. Enable Setting
Launch Karabiner-Elements
Complex Modifications > Rules > [Add rule]
Enable rule 'Terminal等でESC時に日本語入力を英数に'
Restart Terminal or Cloud9

[参考]
https://qiita.com/takaeda/items/38ecf7d98d1a3ef99ef0