Home row as arrows using Karabiner Elements

home_row_arrows.json

{
    "title": "Home row cursor",
    "rules": [
        {
            "description": "Change fn + H/J/K/L to Arrow Keys",
            "manipulators": [
                {
                    "type": "basic",
                    "from": {
                        "key_code": "h",
                        "modifiers": {
                            "mandatory": ["fn"],
                            "optional": ["any"]
                        }
                    },
                    "to": [{"key_code": "left_arrow"}]
                },
                {
                    "type": "basic",
                    "from": {
                        "key_code": "j",
                        "modifiers": {
                            "mandatory": ["fn"],
                            "optional": ["any"]
                        }
                    },
                    "to": [{"key_code": "down_arrow"}]
                },
                {
                    "type": "basic",
                    "from": {
                        "key_code": "k",
                        "modifiers": {
                            "mandatory": ["fn"],
                            "optional": ["any"]
                        }
                    },
                    "to": [{"key_code": "up_arrow"}]
                },
                {
                    "type": "basic",
                    "from": {
                        "key_code": "l",
                        "modifiers": {
                            "mandatory": ["fn"],
                            "optional": ["any"]
                        }
                    },
                    "to": [{"key_code": "right_arrow"}]
                }
            ]
        }
    ]
}