---
id: fast-element.fastelementdefinition.isdefined
title: FASTElementDefinition.isDefined property
hide_title: true
---
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[@microsoft/fast-element](./fast-element.md) &gt; [FASTElementDefinition](./fast-element.fastelementdefinition.md) &gt; [isDefined](./fast-element.fastelementdefinition.isdefined.md)

## FASTElementDefinition.isDefined property

Indicates if this element has been defined in at least one registry.

<b>Signature:</b>

```typescript
get isDefined(): boolean;
```