# Events Batch allows you to track events that happen in your application. They automatically keep track of their count, the last time it happened and their value. > **Important**\ > \- Please [read our guide](https://doc.batch.com/getting-started/other/overview-guides/01-custom-data) on custom data before tagging your app.\ > \- Newly tracked events are hidden by default. You will need to manually display them from the dashboard settings > ["Custom data" tab](https://doc.batch.com/getting-started/other/overview-guides/01-custom-data#using-your-custom-data). ### Tracking events Events are easy to use, but have some rules: * Event names are strings. They should be made of letters, numbers or underscores *(\[a-z0-9\_])* and can't be longer than 30 characters. * A custom data object can be attached. See the section "Event Attributes", right under this one. * Custom attributes have some reserved keys. See the section "Reserved event attributes" under "Event Attributes" for more info. Here's an example: ```javascript import { BatchProfile } from '@batch.com/react-native-plugin'; // Simple event BatchProfile.trackEvent("ad_seen") // Event with custom attributes BatchProfile.trackEvent("add_to_cart", new BatchEventAttributes() // Custom attributes .put("sub_category", "bags") // Compatibility reserved key .put("$label", "activity") ); ``` #### Event attributes Custom attributes can be attached to events using `BatchEventAttributes`. You will then use them when calling `BatchProfile.trackEvent()`. Attribute names are **strings**. They should be made of letters, numbers or underscores *(\[a-z0-9\_])* and can't be longer than 30 characters *(e.g. has\_premium)*. They will be automatically lowercased, so trying to use the same key with different casing will overwrite the previously set value. Values must be any of the following types: * **String** must not be longer than 200 characters and can't be empty. For better results, you should make them upper/lowercase and trim the whitespaces. * **Number**. * **Boolean** * **Date** * **URL** not longer than 2048 characters and must follow the format `scheme://[authority][path][?query][#fragment]` * **Array\**, You can set array of strings (max 200chars) and array of objects. Max 25 items. You cannot mix several attribute types in one array. Arrays can't be nested. * **Object** (using `BatchEventAttributes`, Objects cannot have more than 3 levels of nesting. {% hint style="info" %} Setting a value for an existing key will overwrite it. Any attempt to add an invalid attribute will fail and the event will **NOT** be tracked. You can catch for a list of human-readable errors. {% endhint %} **Reserved event attributes** Some event attributes have reserved keys, and are all prefixed by a `$` sign. This is the list of currently reserved event attributes. You cannot set an event attribute starting by a *$* sign.
IdDescription
$labelString - Optional
Event label. Must be a string, will automatically be bridged as label for application event compatibility. Max 200 chars.
$tagsList - Optional
Event tags. Must be an array of string, will automatically be bridged as tags for application event compatibility. Max 10 items of type string, each no longer than 64chars. The SDK will automatically lowercase them, so two same strings with different casing do not count as two different tags
In Batch React-Native Plugin v8 you were able to set a label and tags at the root of an event, with the limit of 1 label and 10 tags. Batch React-Native Plugin v9 introduced Object and Array types in event attributes. You can set more than one array on profiles events. This is only supported for profiles, and not on the install-centric data model, which currently powers push notification and In-App messages. However, it's still possible to set a label and tags on events in the install-centric data model by using `$label` and `$tags`, and activate compatibility flows. This way, you will be able to use this data for your push and in-app communications. Example: ```javascript const attributes = new BatchEventAttributes() .put('delivery_address', new BatchEventAttributes() .put('number', 43) .put('street', 'Rue Beaubourg') .put('zip_code', 75003) .put('city', 'Paris') .put('country', 'France'), ) .put('number', 43) .putDate('date', new Date().getTime()) .put('items_list', [ new BatchEventAttributes() .put('name', 'Basic Tee') .put('size', 'M') .put('price', 23.99) .putURL('item_url', 'https://batch-store.com/basic-tee') .putURL('item_image', 'https://batch-store.com/basic-tee/black/image.png', ) .put('in_sales', true), new BatchEventAttributes() .put('name', 'Short socks pack x3') .put('size', '38-40') .put('price', 15.99) .putURL('item_url', 'https://batch-store.com/short-socks-pack-x3') .putURL('item_image', 'https://batch-store.com/short-socks-pack-x3/image.png', ) .put('in_sales', false), ]) .put('metadata', ['first_purchase', 'apple_pay']) .put('$label', 'accessories') .put('$tags', ['first_purchase', 'in_promo']); BatchProfile.trackEvent('validated_purchase', attributes).catch(e => console.log(e), ); ``` ### Tracking user location You can now natively track a user location. You will have to wrap the location in a plain object defining: * `latitude` (number) * `longitude` (number) * `date` (Date, optional) * `precision` (number, optional) precision radius in meters Here it's typescript definition of the object: ```typescript /** * Represents a locations, using lat/lng coordinates */ interface Location { /** * Latitude */ latitude: number; /** * Longitude */ longitude: number; /** * Date of the tracked location */ date?: Date; /** * Precision radius in meters */ precision?: number; } ``` And an: ```javascript BatchProfile.trackLocation({ date: new Date(), // Optionnal latitude: 45.764042, longitude: 4.835659, precision: 125 // Optionnal }) ``` This data will allow you to send [geotargeted push notifications](https://doc.batch.com/getting-started/features/mobile-engagement-platform/03-push/02-user-targeting) from the dashboard or the Campaigns API. {% hint style="info" %} The SDK will throttle location tracking to optimize network and battery usage. You can track one location event every 30 seconds, any attempt at updating the location sooner will be ignored by the SDK. {% endhint %}