ARM template if example

ifArm.json

{
    "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
        "changeVariable": {
            "type": "string",
            "defaultValue": "yes",
            "allowedValues": [
                "yes",
                "no"
            ]
        }
    },
    "variables": {
        "var1": "defaultValue"
    },
    "resources": [],
    "outputs": {
        "equalsOutput": {
            "type": "bool",
            "value": "[equals(parameters('changeVariable'), 'yes')]"
        },
        "output": {
            "type": "string",
            "value": "[if(equals(parameters('changeVariable'), 'yes'), variables('var1'), 'changedValue')]"
        }
    }
}