# parseTopoJSON

Geo Map: decode TopoJSON without changing data. Returns null for other chart types or an unavailable child.

Canonical: https://chart.syidax.com/docs/methods/parseTopoJSON/

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## Definition

```typescript
parseTopoJSON(input: unknown, objectName?: string): Promise<GeoMapFeatureCollection | null>
```

| Arguments | Type | Required |
| --- | --- | --- |
| `input` | `unknown` | Required |
| `objectName` | `string` | Optional |

Return type: `Promise<GeoMapFeatureCollection | null>`. Call the method after element registration and await its Promise result.

- [GeoMapFeatureCollection](https://chart.syidax.com/docs/types/GeoMapFeatureCollection.md) — Type definition

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## Related charts

- [sy-geo-map](https://chart.syidax.com/docs/components/geo-map.md#method-parseTopoJSON)