Change EN-TH language with Left Option-Left Shift in Karabiner

change-en-th-opt-shift.json

{
    "title": "Language Toggler",
    "rules": [
      {
    "description": "Switch between TH <-> EN (Left Option + Left Shift)",
    "manipulators": [
      {
        "conditions": [
          {
            "input_sources": [
              {
                "language": "en"
              }
            ],
            "type": "input_source_if"
          }
        ],
        "from": {
          "key_code": "left_shift",
          "modifiers": {
            "mandatory": ["left_option"]
          }
        },
        "to": [
          {
            "key_code": "left_shift",
            "modifiers": ["left_option"]
          }
        ],
        "to_if_alone": [
          {
            "select_input_source": {
              "language": "th"
            }
          }
        ],
        "type": "basic"
      },
      {
        "conditions": [
          {
            "input_sources": [
              {
                "language": "th"
              }
            ],
            "type": "input_source_if"
          }
        ],
        "from": {
          "key_code": "left_shift",
          "modifiers": {
            "mandatory": ["left_option"]
          }
        },
        "to": [
          {
            "key_code": "left_shift",
            "modifiers": ["left_option"]
          }
        ],
        "to_if_alone": [
          {
            "select_input_source": {
              "language": "en"
            }
          }
        ],
        "type": "basic"
      }
    ]
  }
  
    ]
  }