[Home](./index.md) > [@firebase/analytics](./analytics.md) > [logEvent](./analytics.logevent_9.md)
## logEvent() function
Sends analytics event with given `eventParams`. This method automatically associates this logged event with this Firebase web app instance on this device.
List of recommended event parameters can be found in [the gtag.js reference documentation](https://developers.google.com/gtagjs/reference/event).
Signature:
```typescript
export declare function logEvent(analyticsInstance: Analytics, eventName: 'purchase' | 'refund', eventParams?: {
value?: EventParams['value'];
currency?: EventParams['currency'];
transaction_id: EventParams['transaction_id'];
tax?: EventParams['tax'];
shipping?: EventParams['shipping'];
items?: EventParams['items'];
coupon?: EventParams['coupon'];
affiliation?: EventParams['affiliation'];
[key: string]: any;
}, options?: AnalyticsCallOptions): void;
```
## Parameters
| Parameter | Type | Description |
| --- | --- | --- |
| analyticsInstance | [Analytics](./analytics.analytics.md) | |
| eventName | 'purchase' \| 'refund' | |
| eventParams | { value?: [EventParams](./analytics.eventparams.md)\['value'\]; currency?: [EventParams](./analytics.eventparams.md)\['currency'\]; transaction\_id: [EventParams](./analytics.eventparams.md)\['transaction\_id'\]; tax?: [EventParams](./analytics.eventparams.md)\['tax'\]; shipping?: [EventParams](./analytics.eventparams.md)\['shipping'\]; items?: [EventParams](./analytics.eventparams.md)\['items'\]; coupon?: [EventParams](./analytics.eventparams.md)\['coupon'\]; affiliation?: [EventParams](./analytics.eventparams.md)\['affiliation'\]; \[key: string\]: any; } | |
| options | [AnalyticsCallOptions](./analytics.analyticscalloptions.md) | |
Returns:
void