tessl/npm-polkadot--util

A collection of useful utilities for @polkadot ecosystem with type checking, data conversion, and performance optimization functions

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Type Checking Utilities

Name: tessl/npm-polkadot--util
Author: tessl

Comprehensive runtime type validation utilities for JavaScript/TypeScript applications, providing 28 functions to check data types, formats, and object characteristics with full type guard support.

Capabilities

Basic Type Checking

Core type validation functions with TypeScript type guards.

/**
 * Checks if value is a string
 */
function isString(value: unknown): value is string;

/**
 * Checks if value is a number (excluding NaN)
 */
function isNumber(value: unknown): value is number;

/**
 * Checks if value is a boolean
 */
function isBoolean(value: unknown): value is boolean;

/**
 * Checks if value is an array
 */
function isArray(value: unknown): value is unknown[];

/**
 * Checks if value is an object (excluding null and arrays)
 */
function isObject(value: unknown): value is Record<string, unknown>;

/**
 * Checks if value is a function
 */
function isFunction(value: unknown): value is Function;

/**
 * Checks if value is null
 */
function isNull(value: unknown): value is null;

/**
 * Checks if value is undefined
 */
function isUndefined(value: unknown): value is undefined;

/**
 * Checks if value is an Error instance
 */
function isError(value: unknown): value is Error;

Specialized Type Checking

Advanced type checking for specific data types and formats.

/**
 * Checks if value is a BigInt
 */
function isBigInt(value: unknown): value is bigint;

/**
 * Checks if value is a BN (big number) instance
 */
function isBn(value: unknown): value is BN;

/**
 * Checks if value is a Uint8Array
 */
function isU8a(value: unknown): value is Uint8Array;

/**
 * Checks if value is a Buffer
 */
function isBuffer(value: unknown): value is Buffer;

/**
 * Checks if value is a Promise
 */
function isPromise(value: unknown): value is Promise<unknown>;

/**
 * Checks if value is an Observable (RxJS-like)
 */
function isObservable(value: unknown): value is Observable;

Format Validation

Functions for validating string formats and data structures.

/**
 * Checks if string is valid hexadecimal
 * @param value - String to check
 * @param bitLength - Expected bit length (optional)
 * @param ignoreLength - Whether to ignore length validation
 */
function isHex(value: unknown, bitLength?: number, ignoreLength?: boolean): value is HexString;

/**
 * Checks if string contains only ASCII characters
 */
function isAscii(value: unknown): value is string;

/**
 * Checks if Uint8Array contains valid UTF-8 data
 */
function isUtf8(value: Uint8Array): boolean;

/**
 * Checks if string is a valid IP address (IPv4 or IPv6)
 */
function isIp(value: unknown): value is string;

/**
 * Checks if value is a valid JSON object
 */
function isJsonObject(value: unknown): value is Record<string, unknown>;

/**
 * Checks if value is compact encoded (SCALE)
 */
function isCompact(value: unknown): boolean;

Class and Instance Checking

Utilities for checking class relationships and instances.

/**
 * Checks if value is a class constructor
 */
function isClass(value: unknown): value is Class;

/**
 * Checks if value is an instance of specified constructor
 * @param value - Value to check
 * @param clazz - Constructor function
 */
function isInstanceOf(value: unknown, clazz: Class): boolean;

/**
 * Checks if child class extends parent class
 * @param Child - Child class constructor
 * @param Parent - Parent class constructor
 */
function isChildClass(Child: Class, Parent: Class): boolean;

Method Interface Checking

Functions to check if objects implement specific method interfaces.

/**
 * Checks if object has toBn method
 */
function isToBn(value: unknown): value is ToBn;

/**
 * Checks if object has toBigInt method
 */
function isToBigInt(value: unknown): value is ToBigInt;

/**
 * Checks if object has codec methods (toHex, toU8a, etc.)
 */
function isCodec(value: unknown): boolean;

Environment and System Checking

Platform and environment detection utilities.

/**
 * Checks if running on RISC-V architecture
 */
function isRiscV(): boolean;

/**
 * Checks if chain is a test chain (based on genesis hash)
 */
function isTestChain(genesisHash: string | Uint8Array): boolean;

/**
 * Checks if value is a WebAssembly module
 */
function isWasm(value: unknown): value is WebAssembly.Module;

Usage Examples

Basic Type Validation:

import { isString, isNumber, isHex, isU8a } from "@polkadot/util";

function processData(input: unknown) {
  if (isString(input)) {
    // TypeScript knows input is string here
    return input.toUpperCase();
  }
  
  if (isNumber(input)) {
    // TypeScript knows input is number here
    return input * 2;
  }
  
  throw new Error("Invalid input type");
}

Format Validation:

import { isHex, isU8a, hexToU8a } from "@polkadot/util";

function convertToBytes(input: string | Uint8Array): Uint8Array {
  if (isU8a(input)) {
    return input;
  }
  
  if (isHex(input)) {
    return hexToU8a(input);
  }
  
  throw new Error("Input must be hex string or Uint8Array");
}

Interface Checking:

import { isToBn, bnToBn } from "@polkadot/util";

function convertToBn(value: unknown) {
  if (isToBn(value)) {
    // Value has toBn() method
    return value.toBn();
  }
  
  // Fallback to general conversion
  return bnToBn(value);
}

Types

interface Observable {
  next(value?: unknown): unknown;
}

interface Class<T = unknown> {
  new (...args: unknown[]): T;
}

interface ToBn {
  toBn(): BN;
}

interface ToBigInt {
  toBigInt(): bigint;
}

type HexString = `0x${string}`;

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