# $evaluateExpression(expression: string, itemIndex: number)

Evaluates a given string as expression.
If no `itemIndex` is provided it uses by default in the Function-Node the data of item 0 and
in the Function Item-Node the data of the current item.

Example:

```javascript
items[0].json.variable1 = $evaluateExpression('{{1+2}}');
items[0].json.variable2 = $evaluateExpression($node["Set"].json["myExpression"], 1);

return items;
```