@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:

🧰 Functions

• convertStringToE8s
• isNullish
• nonNullish
• notEmptyString
• defaultAgent
• createAgent
• createServices
• assertNonNullish
• asNonNullish
• assertPercentageNumber
• uint8ArrayToBigInt
• bigIntToUint8Array
• numberToUint8Array
• arrayBufferToUint8Array
• uint8ArrayToArrayOfNumber
• arrayOfNumberToUint8Array
• asciiStringToByteArray
• hexStringToUint8Array
• uint8ArrayToHexString
• candidNumberArrayToBigInt
• encodeBase32
• decodeBase32
• bigEndianCrc32
• secondsToDuration
• debounce
• toNullable
• fromNullable
• fromDefinedNullable
• jsonReplacer
• jsonReviver
• principalToSubAccount
• smallerVersion

⚙️ convertStringToE8s

Receives a string representing a number and returns the big int or error.

Function	Type
convertStringToE8s	(value: string) => bigint or FromStringToTokenError

Parameters:

• amount: - in string format

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⚙️ isNullish

Is null or undefined

Function	Type
isNullish	<T>(argument: T or null or undefined) => argument is null or undefined

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⚙️ nonNullish

Not null and not undefined

Function	Type
nonNullish	<T>(argument: T or null or undefined) => argument is NonNullable<T>

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⚙️ notEmptyString

Not null and not undefined and not empty

Function	Type
notEmptyString	(value: string or null or undefined) => boolean

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⚙️ defaultAgent

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

Function	Type
defaultAgent	() => Agent

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⚙️ createAgent

Create an agent for a given identity

Function	Type
createAgent	({ identity, host, fetchRootKey, verifyQuerySignatures, retryTimes, }: CreateAgentParams) => Promise<HttpAgent>

Parameters:

• params: The parameters to create a new HTTP agent
• params.identity: A mandatory identity to use for the agent
• params.host: An optional host to connect to, particularly useful for local development
• params.fetchRootKey: Fetch root key for certificate validation during local development or on testnet
• params.verifyQuerySignatures: Check for signatures in the state tree signed by the node that replies to queries - i.e. certify responses.
• params.retryTimes: Set the number of retries the agent should perform before error.

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⚙️ createServices

Function	Type
createServices	<T>({ options: { canisterId, serviceOverride, certifiedServiceOverride, agent: agentOption, callTransform, queryTransform, }, idlFactory, certifiedIdlFactory, }: { options: Required<Pick<CanisterOptions<T>, "canisterId">> and Omit<CanisterOptions<T>, "canisterId"> and Pick<...>; idlFactory: InterfaceFactory; certifiedId...

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⚙️ assertNonNullish

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

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⚙️ asNonNullish

Function	Type
asNonNullish	<T>(value: T, message?: string or undefined) => NonNullable<T>

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⚙️ assertPercentageNumber

Function	Type
assertPercentageNumber	(percentage: number) => void

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⚙️ uint8ArrayToBigInt

Function	Type
uint8ArrayToBigInt	(array: Uint8Array) => bigint

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⚙️ bigIntToUint8Array

Function	Type
bigIntToUint8Array	(value: bigint) => Uint8Array

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⚙️ numberToUint8Array

Function	Type
numberToUint8Array	(value: number) => Uint8Array

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⚙️ arrayBufferToUint8Array

Function	Type
arrayBufferToUint8Array	(buffer: ArrayBuffer) => Uint8Array

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⚙️ uint8ArrayToArrayOfNumber

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

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⚙️ arrayOfNumberToUint8Array

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

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⚙️ asciiStringToByteArray

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

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⚙️ hexStringToUint8Array

Function	Type
hexStringToUint8Array	(hexString: string) => Uint8Array

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⚙️ uint8ArrayToHexString

Function	Type
uint8ArrayToHexString	(bytes: Uint8Array or number[]) => string

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⚙️ candidNumberArrayToBigInt

Function	Type
candidNumberArrayToBigInt	(array: number[]) => bigint

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⚙️ encodeBase32

Encode an Uint8Array to a base32 string.

Function	Type
encodeBase32	(input: Uint8Array) => string

Parameters:

• input: The input array to encode.

🔗 Source

⚙️ decodeBase32

Decode a base32 string to Uint8Array.

Function	Type
decodeBase32	(input: string) => Uint8Array

Parameters:

• input: The input string to decode.
• input: The base32 encoded string to decode.

🔗 Source

⚙️ bigEndianCrc32

Function	Type
bigEndianCrc32	(bytes: Uint8Array) => Uint8Array

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⚙️ secondsToDuration

Convert seconds to a human-readable duration, such as "6 days, 10 hours."

Function	Type
secondsToDuration	({ seconds, i18n, }: { seconds: bigint; i18n?: I18nSecondsToDuration or undefined; }) => string

Parameters:

• options: - The options object.
• options.seconds: - The number of seconds to convert.
• options.i18n: - The i18n object for customizing language and units. Defaults to English.

🔗 Source

⚙️ debounce

Function	Type
debounce	(func: Function, timeout?: number or undefined) => (...args: unknown[]) => void

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⚙️ toNullable

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

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⚙️ fromNullable

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

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⚙️ fromDefinedNullable

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

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⚙️ jsonReplacer

A parser that interprets revived BigInt, Principal, and Uint8Array when constructing JavaScript values or objects.

Function	Type
jsonReplacer	(_key: string, value: unknown) => unknown

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⚙️ jsonReviver

A function that alters the behavior of the stringification process for BigInt, Principal and Uint8Array.

Function	Type
jsonReviver	(_key: string, value: unknown) => unknown

🔗 Source

⚙️ 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

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⚙️ smallerVersion

Returns true if the current version is smaller than the minVersion, false if equal or bigger. Tags after patch version are ignored, e.g. 1.0.0-beta.1 is considered equal to 1.0.0.

Function	Type
smallerVersion	({ minVersion, currentVersion, }: { minVersion: string; currentVersion: string; }) => boolean

Parameters:

• params.minVersion: Ex: "1.0.0"
• params.currentVersion: Ex: "2.0.0"

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🔧 Constants

• E8S_PER_TOKEN
• ICPToken

⚙️ E8S_PER_TOKEN

Constant	Type
E8S_PER_TOKEN	bigint

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⚙️ ICPToken

Constant	Type
ICPToken	Token

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🏭 TokenAmount

Deprecated. Use TokenAmountV2 instead which supports decimals !== 8.

Represents an amount of tokens.

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Methods

• fromE8s
• fromString
• fromNumber
• toE8s

⚙️ fromE8s

Initialize from a bigint. Bigint are considered e8s.

Method	Type
fromE8s	({ amount, token, }: { amount: bigint; token: Token; }) => TokenAmount

Parameters:

• params.amount: The amount in bigint format.
• params.token: The token type.

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⚙️ fromString

Initialize from a string. Accepted formats:

1234567.8901 1'234'567.8901 1,234,567.8901

Method	Type
fromString	({ amount, token, }: { amount: string; token: Token; }) => FromStringToTokenError or TokenAmount

Parameters:

• params.amount: The amount in string format.
• params.token: The token type.

🔗 Source

⚙️ fromNumber

Initialize from a number.

1 integer is considered E8S_PER_TOKEN

Method	Type
fromNumber	({ amount, token, }: { amount: number; token: Token; }) => TokenAmount

Parameters:

• params.amount: The amount in number format.
• params.token: The token type.

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⚙️ toE8s

Method	Type
toE8s	() => bigint

🔗 Source

🏭 TokenAmountV2

Represents an amount of tokens.

🔗 Source

Methods

• fromUlps
• fromString
• fromNumber
• toUlps
• toE8s

⚙️ fromUlps

Initialize from a bigint. Bigint are considered ulps.

Method	Type
fromUlps	({ amount, token, }: { amount: bigint; token: Token; }) => TokenAmountV2

Parameters:

• params.amount: The amount in bigint format.
• params.token: The token type.

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⚙️ fromString

Initialize from a string. Accepted formats:

1234567.8901 1'234'567.8901 1,234,567.8901

Method	Type
fromString	({ amount, token, }: { amount: string; token: Token; }) => FromStringToTokenError or TokenAmountV2

Parameters:

• params.amount: The amount in string format.
• params.token: The token type.

🔗 Source

⚙️ fromNumber

Initialize from a number.

1 integer is considered 10^{token.decimals} ulps

Method	Type
fromNumber	({ amount, token, }: { amount: number; token: Token; }) => TokenAmountV2

Parameters:

• params.amount: The amount in number format.
• params.token: The token type.

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⚙️ toUlps

Method	Type
toUlps	() => bigint

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⚙️ toE8s

Method	Type
toE8s	() => bigint

🔗 Source

🏭 Canister

🔗 Source

🏭 AgentManager

AgentManager class manages HttpAgent instances for different identities.

It caches agents by identity to optimise resource usage and avoid unnecessary agent creation. Provides functionality to create new agents, retrieve cached agents, and clear the cache when needed.

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Methods

• create
• getAgent
• clearAgents

⚙️ create

Static factory method to create a new AgentManager instance.

This method serves as an alternative to directly using the private constructor, making it more convenient to create instances of AgentManager using a simple and clear method.

Method	Type
create	(config: AgentManagerConfig) => AgentManager

Parameters:

• config: - Configuration options for the AgentManager instance.
• config.fetchRootKey: - Whether to fetch the root key for certificate validation.
• config.host: - The host to connect to.

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⚙️ getAgent

Get or create an HTTP agent for a given identity.

If the agent for the specified identity has been created and cached, it is retrieved from the cache. If no agent exists for the identity, a new one is created, cached, and then returned.

Method	Type
getAgent	({ identity, }: { identity: Identity; }) => Promise<HttpAgent>

Parameters:

• identity: - The identity to be used to create the agent.

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⚙️ clearAgents

Clear the cache of HTTP agents.

This method removes all cached agents, forcing new agent creation on the next request for any identity. Useful when identities have changed or if you want to reset all active connections.

Method	Type
clearAgents	() => void

🔗 Source

🏭 InvalidPercentageError

🔗 Source

🏭 NullishError

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