# Mappings

Mappings are generally needed when datasets or `Lists` are assigned to other `Lists` with different properties.

This example maps the result of a query (StadiumTestData\_CitiesSelect) with the properties of `Name` and `CountryCode` to a control that expects `text` and `value` properties.

```javascript
await ~.StadiumTestData_CitiesSelect.Results.mapAsync(async MapItem => ({
	text: MapItem.Name,
	value: MapItem.CountryCode
}))
```

## Mapping Editor

Properties of an incoming `List` of objects can be mapped to `List` properties when names of the properties of the assigned data differ from the `List` `Item Type` properties. For this purpose, select the `Field Mapping` option in the `List` `Value` property dropdown.

![](https://3514041584-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqxH8JA8xG3I22tiZG5H6%2Fuploads%2Fgit-blob-e1b0a944401274f088048d6bcdee19de75c6116e%2FFieldMappingOption.png?alt=media)

The `Mapping Editor` displays information in two columns, the target information on the left and the source on the right.

![](https://3514041584-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FqxH8JA8xG3I22tiZG5H6%2Fuploads%2Fgit-blob-f96785ea152824d76768b952232568a933d51fa9%2FMappingEditor.png?alt=media)

The target information column (left) provides the

1. Target List
2. All mappable properties of the Target

The source column (right) provides

1. A dropdown to select the source data `List`
2. Input fields to define the mapping for source List properties. The `MapItem` option in the dropdown represents a `List Item`. Where such an item consists of a known type, the type properties are provided for selection.