@dfinity/utils

utils-js

A collection of utilities and constants for NNS/SNS projects.

Table of contents

• Installation
• Features

Installation

You can use utils-js by installing it in your project.

npm i @dfinity/utils

The bundle needs peer dependencies, be sure that following resources are available in your project as well.

npm i @dfinity/agent @dfinity/candid @dfinity/principal

Features

utils-js implements following features:

:toolbox: Functions

• defaultAgent
• createAgent
• createServices
• uint8ArrayToBigInt
• arrayBufferToUint8Array
• uint8ArrayToArrayOfNumber
• arrayOfNumberToUint8Array
• asciiStringToByteArray
• assertNonNullish
• toNullable
• fromNullable
• fromDefinedNullable
• principalToSubAccount

:gear: defaultAgent

Get a default agent that connects to mainnet with the anonymous identity.

Function	Type
defaultAgent	() => Agent

:gear: createAgent

Create an agent for a given identity

Function	Type
createAgent	({ identity, host, fetchRootKey, }: { identity: Identity; host?: string; fetchRootKey?: boolean; }) => Promise<HttpAgent>

Parameters:

• identity: A mandatory identity to use for the agent
• host: An optional host to connect to
• fetchRootKey: Fetch root key for certificate validation during local development or on testnet

:gear: createServices

Function	Type
createServices	<T>({ options: { canisterId, serviceOverride, certifiedServiceOverride, agent: agentOption, }, idlFactory, certifiedIdlFactory, }: { options: RequiredCanisterOptions<T>; idlFactory: InterfaceFactory; certifiedIdlFactory: InterfaceFactory; }) => { ...; }

:gear: uint8ArrayToBigInt

Function	Type
uint8ArrayToBigInt	(array: Uint8Array) => bigint

:gear: arrayBufferToUint8Array

Function	Type
arrayBufferToUint8Array	(buffer: ArrayBuffer) => Uint8Array

:gear: uint8ArrayToArrayOfNumber

Function	Type
uint8ArrayToArrayOfNumber	(array: Uint8Array) => number[]

:gear: arrayOfNumberToUint8Array

Function	Type
arrayOfNumberToUint8Array	(numbers: number[]) => Uint8Array

:gear: asciiStringToByteArray

Function	Type
asciiStringToByteArray	(text: string) => number[]

:gear: assertNonNullish

Function	Type
assertNonNullish	<T>(value: T, message?: string) => asserts value is NonNullable<T>

:gear: toNullable

Function	Type
toNullable	<T>(value?: T) => [] or [T]

:gear: fromNullable

Function	Type
fromNullable	<T>(value: [] or [T]) => T

:gear: fromDefinedNullable

Function	Type
fromDefinedNullable	<T>(value: [] or [T]) => T

:gear: principalToSubAccount

Convert a principal to a Uint8Array 32 length. e.g. Useful to convert a canister ID when topping up cycles with the Cmc canister

Function	Type
principalToSubAccount	(principal: Principal) => Uint8Array

Parameters:

• principal: The principal that needs to be converted to Subaccount

:factory: NullishError

Constructors

public

Parameters:

• message