An example using configuration variables within Arc.js

arcjs_configuration_demo.json

{
  "actions": [
    {
      "actionId": "http.commerce.catalog.storefront.shipping.requestRates.after",
      "contexts": [
        {
          "customFunctions": [
            {
              "applicationKey": "DevTrain.AMSXBG_Arc.1.0.0.Release",
              "functionId": "http.commerce.catalog.storefront.shipping.requestRates.after",
              "enabled": true,
              "configuration": {
                "shippingPercentage": 0.75,
                "increaseRate": false,
                "roundDown": false
              }
            }
          ]
        }
      ]
    }
  ],
  "configurations": [
    {
      "configuration": {
        "shippingPercentage": 0.5
      }
    }
  ],
  "defaultLogLevel": "error"
}