to.set_variable

set_variable defines and updates the variable value.

Tip

set_variable is designed to use with the following conditions:

Examples

Pressing the a key while holding the escape key launches Activity Monitor.

{
    "description": "Pressing the a key while holding the escape key launches Activity Monitor",
    "manipulators": [
        {
            "type": "basic",
            "from": {
                "key_code": "escape",
                "modifiers": { "optional": ["any"] }
            },
            "to": [
                {
                    "set_variable": {
                        "name": "escape_pressed",
                        "value": true,
                        "key_up_value": false
                    }
                }
            ],
            "to_if_alone": [{ "key_code": "escape" }]
        },
        {
            "type": "basic",
            "from": {
                "key_code": "a",
                "modifiers": { "optional": ["any"] }
            },
            "to": [
                {
                    "software_function": {
                        "open_application": {
                            "bundle_identifier": "com.apple.ActivityMonitor"
                        }
                    }
                }
            ],
            "conditions": [
                {
                    "type": "variable_if",
                    "name": "escape_pressed",
                    "value": true
                }
            ]
        }
    ]
}

Specification

{
    "to": [
        {
            "set_variable": {
                "name": "variable name",
                "value": variable value,
                "expression": expression,
                "key_up_value": variable value,
                "key_up_expression": expression,
                "type": "set"
            }
        }
    ]
}

Name	Required	Description	Available since
`name`	Required	Target variable name.	Karabiner-Elements 11.0.0
`value`	Required \| Optional	Target variable value.	Karabiner-Elements 11.0.0
`expression`	Required \| Optional	Target expression.	Karabiner-Elements 15.5.19
`key_up_value`	Optional	A variable value when key is up	Karabiner-Elements 14.12.6
`key_up_expression`	Optional	An expression when key is up	Karabiner-Elements 15.5.19
`type`	Optional	“set” or “unset”	Karabiner-Elements 14.99.2

Note: If key_up_value or type is specified, the value can be omitted.

Available types of `value`

Type	Example value	Available since
integer	0,1,2,…	Karabiner-Elements 11.0.0
boolean	true, false	Karabiner-Elements 14.4.20
string	“layer1”, “layer2”	Karabiner-Elements 14.4.20

Expression specification

expression and key_up_expression are available since Karabiner-Elements 15.5.19.

expression and key_up_expression allow you to write arithmetic expressions, and you can use variables set by other set_variable manipulations and the following system-provided variables. If an undefined variable appears in the expression, its value is treated as 0.

system.now.milliseconds
system.scroll_direction_is_natural
system.use_fkeys_as_standard_function_keys

The arithmetic syntax used in expression and key_up_expression follows exprtk.

Expression examples

Change right_shift x2 to mission_control.

💡 How to use this example

{
    "description": "Change right_shift x2 to mission_control",
    "manipulators": [
        {
            "type": "basic",
            "from": {
                "key_code": "right_shift",
                "modifiers": { "optional": ["any"] }
            },
            "to": [
                { "apple_vendor_keyboard_key_code": "mission_control" },
                { "key_code": "vk_none" }
            ],
            "conditions": [
                {
                    "type": "expression_if",
                    "expression": "right_shift_x2_expiration > system.now.milliseconds"
                }
            ]
        },
        {
            "type": "basic",
            "from": {
                "key_code": "right_shift",
                "modifiers": { "optional": ["any"] }
            },
            "to": [
                {
                    "set_variable": {
                        "name": "right_shift_x2_expiration",
                        "expression": "system.now.milliseconds + 300"
                    }
                },
                { "key_code": "right_shift" }
            ]
        }
    ]
}

Confirm the current variable values

You can see the current variable values by EventViewer > Variables.