# Actions in Rules

Actions define what a rule does. Use constants to make it easier to perform any action.

## Actions

Actions define the way rules change an app’s JSON files. Valid actions are:

- `delete`: Delete a node in the document.
- `put`: Add a node to an object.
- `set`: Set the value of an existing node in the document.
- `add`: Add an element to an array
- `eval`: Evaluate a specified expression and assign results to a variable.
- `replace`: Search and replace a text string globally.

Each action has a path attribute, which is a [JsonPath](http://goessner.net/articles/JsonPath/) that points to a node in the document. JsonPath is to JSON as XPath is to XML. Practice it in the [Jayway JsonPath Evaluator](http://jsonpath.herokuapp.com).

:::note
If a template is updated to change the `assetVersion`, it can impact the JsonPath. Always test the rules for app creation after a template update.
:::

Actions can be conditionally applied to a document. Set the condition on a set of actions or on a collection of actions.