JavaScript code API Reference

JavaScript source code for a Functions request should comply with certain restrictions:

Allowed Modules: Only vanilla Deno is supported, without module imports.
Return Type: Must return a JavaScript Buffer object representing the response bytes sent back to the invoking contract.
Time Limit: Scripts must execute within a 10-second timeframe; otherwise, they will be terminated, and an error will be returned to the requesting contract.

HTTP Requests

For making HTTP requests, use the Functions.makeHttpRequest function.

Syntax

const response = await Functions.makeHttpRequest({
  url: "http://example.com",
  method: "GET", // Optional
  // Other optional parameters
})

Parameters

Parameter	Optionality	Description	Default Value
`url`	Required	The target URL.	N/A
`method`	Optional	HTTP method to be used.	`'GET'`
`headers`	Optional	HTTP headers for the request.	N/A
`params`	Optional	URL query parameters.	N/A
`data`	Optional	Body content for the request.	N/A
`timeout`	Optional	Maximum request duration in milliseconds.	`3000 ms`
`responseType`	Optional	Expected response type.	`'json'`

Return Object

Response Type	Fields	Description
Success	`data`	Response data sent by the server.
	`status`	Numeric HTTP status code.
	`statusText`	Textual representation of HTTP status.
	`headers`	HTTP headers sent by the server in the response.
Error	`error`	Indicates an error occurred (`true`).
	`message`	Optional error message.
	`code`	Optional error code.
	`response`	Optional server response.

Data Encoding Functions

The Functions library includes several encoding functions, which are useful for preparing data for blockchain contracts.

Function	Input Type	Output Type	Description
`Functions.encodeUint256`	Positive Integer	32-byte `Buffer`	Converts a positive integer to a 32-byte `Buffer` for a `uint256` in Solidity.
`Functions.encodeInt256`	Integer	32-byte `Buffer`	Converts an integer to a 32-byte `Buffer` for an `int256` in Solidity.
`Functions.encodeString`	String	`Buffer`	Converts a string to a `Buffer` for a `string` type in Solidity.

Note: Using these encoding functions is optional. The source code must return a Uint8Array which represents the bytes that are returned on-chain.

const myArr = new Uint8Array(ARRAY_LENGTH)