Data Types

Input Parameter Types

When parameters are passed into JavaScript UDFs, Rockset values will be converted to JavaScript values according to their types, as follows:

Rockset Data Type	Javascript Type	Remarks
`NULL`	`null`
`UNDEFINED`	`null`	Note that this is not mapped to JavaScript `undefined`. You can use JavaScript `undefined` to detect that your function was called with fewer arguments than specified.
`int`	`number`	Note that this will result in loss of precision for values ≥ `2^53`. If you want to handle large integers up to `int64`, see instructions regarding `BigInt` below.
`int`	`BigInt`	When function property `input_convert_int64_to_bigint` is set to `true`
`float`	`number`
`string`	`string`
`bool`	`boolean` or `number`	The parameter value could be a JavaScript `boolean` or a JavaScript `number` and will evaluate to “true” or “false” when used in a boolean expression.
`object`	`object`
`object`	`Map`	When function property `input_convert_object_to_map` is set to `true`
`array`	`array` or `TypedArray`	Note that a Rockset array consisting solely of booleans may be converted to `Uint8Array`.
`date`	`Date`
`time`	`Date`
`datetime`	`Date`
`timestamp`	`Date`

Special Properties for Input Parameters

You can optionally do the following data type conversions on the JavaScript UDF input parameters by setting certain properties on the function definition:

int64 →BigInt
- Set the property input_convert_int64_to_bigint = true
object → Map
- Set the property input_convert_object_to_map = true
For example:

script {{{

export function echo(n) { return n }

echo.input_convert_int64_to_bigint = true

}}}

SELECT _script.echo(9223372036854775807);

The above function will return the correct value 9223372036854775807 since the Rockset datatype will get mapped to BigInt.

If input_convert_int64_to_bigint was not set to true, then the SQL above will return 9223372036854776000 instead, since JavaScript numbers lose precision beyond 2^53.

Output Return Types

JavaScript values returned by the UDF will be converted into Rockset values according to their types, as follows:

Javascript Type	Rockset Data Type	Remarks
`null`	`NULL`
`undefined`	`NULL`	Note that this is not Rockset `UNDEFINED`
`number`	`int` or `float`	Based on whether value is integral or not. It will always return a Rockset float when function property `output_always_convert_number_to_float` is set to true.
`BigInt`	`int` or `error`	Note that Rockset `int` data type are signed 64-bit integers. If value returned in JavaScript BigInt doesn’t fit in Rockset `int`, an error will be thrown.
`string`	`string`
`boolean`	`bool`
`plain JS object`	`object`	The Rockset object will contain all enumerable, non-`Symbol` keys from the JS object. If either of these keys or their corresponding values cannot be converted to Rockset types, an error will be thrown.
`Map`	`object`
`Set`	`array`
`array`	`array`
`TypedArray`	`array`	Except `Uint8Array`, see below.
`Uint8Array`	`array` of `bool`	Note that the values in the JavaScript `Uint8Array` are interpreted as `boolean` instead of `number`.
`Date`	`timestamp`

Special Properties for Output Return Types

You can optionally do the following data type conversions on the JavaScript UDF return values by setting certain properties on the function definition:

number -> float
- Set the property output_always_convert_number_to_float = true

For Example:

script {{{

export function echo(n) { return n }

echo.output_always_convert_number_to_float = true

}}}

SELECT typeof(_script.echo(10));

The above function will return float. But if output_always_convert_number_to_float was not set to true, then it will return int.