Supported Variables/APIs

To use JavaScript in Usage Engine, there are some mandatory variables and APIs that you require.

Variables/Functions	Description	Examples

Variables/Functions	Description	Examples
audit	To control the custom user audit function. The supported types are: count: Increments the string key value with 1 Syntax `audit.count(key);` sum: Sums up the total amount Syntax `audit.sum(key,value);` set: Sets an input value. Data entry using the set function can be used with any data type. The output of the sum function will show the accumulated amount. Syntax `audit.set(key,value);`	Example - audit.set `audit.set`('Collection 1', JSON.stringify(object)): – This audit function can be used to enter any string value and save it to a specified key. Example - audit.sum `audit.sum`('KEY_NAME', payload.fieldName): - This function is useful when presenting amounts of data that is to be saved or forwarded to a destination source. Example - audit.count `audit.count`('Tracking-Records-Changes'): - This function can be issued to increase the count of tracked records or a collection of data after an audit review.
`log`	An object that contains logging functionality for the severity levels: info, warning, and error. `log.info("foo");` - Logs something to the Usage Engine log. See Logs.
`payload`	The `payload` variable contains all the information of the current record/object.
`meta`	The `meta` variable provides generic information (metadata) about a payload (record). Metadata is data that provide information about other data. Metadata summarises basic information about data, thereby making finding and working with particular instances of data easier. Refer to Amazon S3 \| AmazonS3 S3metadata for more details about metadata that is accessible from the Transform tab. Refer to https://infozone.atlassian.net/wiki/x/E4HFF for more details about the meta data that applies to the Data aggregator. The following metadata is accessible using the Script Flush tab: `lastCall:` A boolean flag set to true for the final transaction. `lastCall` can be used to create a summary or audit for the processed data at the final transaction. To initiate action(s) triggered by the recent transaction:
`push(<event>)`	To send data downstream. You need to invoke this Function using `await` syntax.	To send data to the next Function(s) in the stream.
`state`	This is to keep the state across records. The state is only available during one stream execution. The information stored in the `state` variable is not persisted between executions and is cleared at the end of each stream execution. The `state` variable contains two scopes: node: To save the state locally for this Function. stream: To save the state globally for the stream.
`store`	These three operations functions as a key-value store. The key must be a string. Value can be of any type, for example: string, number, date, JSON object, and array. You need to invoke this Function using `await` syntax: get: To get a value set: To set a value of a key Syntax And, to set the duration (in seconds) of how long the key is stored. Syntax del: To delete a value Syntax
`sharedStore`	With shared persistent storage, streams can access the same data. For example, one stream writes data to the shared persistent storage that can be used by one or more streams. The key must be a string. Value can be of any type, for example, string, number, date, JSON object, and array. You must use the `await` syntax for the Function: sharedStore.get: To get a value. Syntax sharedStore.set: To set a value of a key and the duration (in seconds) of how long the key is stored. Syntax And, to set the duration (in seconds) of how long the key is stored. Syntax sharedStore.del: To delete a value. Syntax

Error message example

This simplistic example shows the log when the keyword "payload" is spelled with a capital 'P'. The following example uses the Summarize Monthly Usage Data example stream.

Syntax

Syntax

Syntax

Error message example