ABI Address Type

Description

This example demonstrates how to encode and decode Algorand addresses using ABIAddressType:

Encoding address strings (base32 format) to 32 bytes
Encoding raw 32-byte public key (Uint8Array)
Decoding bytes back to address string
Verifying address encoding is exactly 32 bytes (no length prefix)
Understanding relationship between Algorand address and public key bytes Algorand addresses are 58 characters in base32 encoding, which includes:
32 bytes of public key
4 bytes of checksum (computed from public key) The ABI encoding is just the raw 32-byte public key without checksum.

Prerequisites

No LocalNet required

Run This Example

From the repository root:

cd examples
npm run example abi/03-address-type.ts

Code

View source on GitHub

/**
 * Example: ABI Address Type
 *
 * This example demonstrates how to encode and decode Algorand addresses using ABIAddressType:
 * - Encoding address strings (base32 format) to 32 bytes
 * - Encoding raw 32-byte public key (Uint8Array)
 * - Decoding bytes back to address string
 * - Verifying address encoding is exactly 32 bytes (no length prefix)
 * - Understanding relationship between Algorand address and public key bytes
 *
 * Algorand addresses are 58 characters in base32 encoding, which includes:
 * - 32 bytes of public key
 * - 4 bytes of checksum (computed from public key)
 *
 * The ABI encoding is just the raw 32-byte public key without checksum.
 *
 * Prerequisites:
 * - No LocalNet required
 */

import { Address, ALGORAND_ZERO_ADDRESS_STRING } from '@algorandfoundation/algokit-utils'
import { ABIAddressType } from '@algorandfoundation/algokit-utils/abi'
import { formatBytes, formatHex, printHeader, printInfo, printStep, printSuccess } from '../shared/utils.js'

function main() {
  printHeader('ABI Address Type Example')

  // Step 1: Create ABIAddressType and inspect properties
  printStep(1, 'ABIAddressType Properties')

  const addressType = new ABIAddressType()

  printInfo(`Type name: ${addressType.toString()}`)
  printInfo(`Byte length: ${addressType.byteLen()} bytes`)
  printInfo(`Is dynamic: ${addressType.isDynamic()}`)

  // Step 2: Encode a base32 address string to bytes
  printStep(2, 'Encode Address String (Base32) to Bytes')

  // Example address - the zero address
  const zeroAddressString = ALGORAND_ZERO_ADDRESS_STRING
  printInfo(`Zero address string: ${zeroAddressString}`)
  printInfo(`Address string length: ${zeroAddressString.length} characters`)

  const zeroEncoded = addressType.encode(zeroAddressString)
  printInfo(`Encoded bytes: ${formatHex(zeroEncoded)}`)
  printInfo(`Encoded length: ${zeroEncoded.length} bytes (exactly 32, no length prefix)`)

  // Verify the zero address encodes to all zeros
  const allZeros = zeroEncoded.every((byte) => byte === 0)
  printInfo(`All bytes are zero: ${allZeros}`)

  // Step 3: Encode another address string
  printStep(3, 'Encode a Real Address String')

  // Create a sample address from a known public key (32 bytes of incrementing values)
  const samplePublicKey = new Uint8Array(32)
  for (let i = 0; i < 32; i++) {
    samplePublicKey[i] = i
  }

  // Create Address object from public key to get base32 string
  const sampleAddress = new Address(samplePublicKey)
  const sampleAddressString = sampleAddress.toString()

  printInfo(`Sample address string: ${sampleAddressString}`)
  printInfo(`Address string length: ${sampleAddressString.length} characters`)

  const sampleEncoded = addressType.encode(sampleAddressString)
  printInfo(`Encoded bytes: ${formatBytes(sampleEncoded, 16)}`)
  printInfo(`Encoded as hex: ${formatHex(sampleEncoded)}`)
  printInfo(`Encoded length: ${sampleEncoded.length} bytes`)

  // Step 4: Encode from raw 32-byte public key (Uint8Array)
  printStep(4, 'Encode from Raw 32-Byte Public Key')

  // ABIAddressType can also encode directly from a Uint8Array
  const rawPublicKey = new Uint8Array([
    0xab, 0xcd, 0xef, 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef,
    0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0x01, 0x23, 0x45, 0x67, 0x89,
  ])

  printInfo(`Raw public key: ${formatHex(rawPublicKey)}`)

  const encodedFromRaw = addressType.encode(rawPublicKey)
  printInfo(`Encoded from raw: ${formatHex(encodedFromRaw)}`)

  // Verify encoding from raw bytes returns the same bytes
  const rawBytesMatch = encodedFromRaw.every((byte, index) => byte === rawPublicKey[index])
  printInfo(`Raw bytes match encoded: ${rawBytesMatch}`)

  // Step 5: Decode bytes back to address string
  printStep(5, 'Decode Bytes Back to Address String')

  // Decode the sample encoded bytes back to address string
  const decodedSampleAddress = addressType.decode(sampleEncoded)
  printInfo(`Original address: ${sampleAddressString}`)
  printInfo(`Decoded address:  ${decodedSampleAddress}`)
  printInfo(`Round-trip verified: ${decodedSampleAddress === sampleAddressString}`)

  // Decode zero address
  const decodedZeroAddress = addressType.decode(zeroEncoded)
  printInfo(`\nOriginal zero address: ${zeroAddressString}`)
  printInfo(`Decoded zero address:  ${decodedZeroAddress}`)
  printInfo(`Round-trip verified: ${decodedZeroAddress === zeroAddressString}`)

  // Decode the raw public key
  const decodedFromRawAddress = addressType.decode(encodedFromRaw)
  printInfo(`\nRaw public key as address: ${decodedFromRawAddress}`)

  // Step 6: Relationship between Algorand address and public key bytes
  printStep(6, 'Address vs Public Key Relationship')

  printInfo('Algorand address format:')
  printInfo('  - Base32 encoded string')
  printInfo('  - 58 characters long')
  printInfo('  - Contains: 32-byte public key + 4-byte checksum')

  printInfo('\nABI address encoding:')
  printInfo('  - Just the raw 32-byte public key')
  printInfo('  - No checksum included')
  printInfo('  - No length prefix (unlike ABI string type)')
  printInfo('  - Fixed size, not dynamic')

  // Demonstrate using Address class directly
  printInfo('\nUsing Address class:')
  const addr = Address.fromString(sampleAddressString)
  printInfo(`  Address.fromString('${sampleAddressString.substring(0, 20)}...')`)
  printInfo(`  .publicKey: ${formatBytes(addr.publicKey, 8)}`)
  printInfo(`  .toString(): ${addr.toString()}`)

  // Show that ABIAddressType encoding equals Address.publicKey
  const publicKeyMatches = addr.publicKey.every((byte, index) => byte === sampleEncoded[index])
  printInfo(`\nABI encoding equals Address.publicKey: ${publicKeyMatches}`)

  // Step 7: Encoding Address object directly
  printStep(7, 'Encode Address Object Directly')

  // ABIAddressType can also accept Address objects
  const addressObject = new Address(rawPublicKey)
  const encodedFromAddressObject = addressType.encode(addressObject)

  printInfo(`Address object: ${addressObject.toString()}`)
  printInfo(`Encoded from Address object: ${formatHex(encodedFromAddressObject)}`)

  const addressObjectMatches = encodedFromAddressObject.every((byte, index) => byte === rawPublicKey[index])
  printInfo(`Encoding matches raw public key: ${addressObjectMatches}`)

  // Step 8: Summary - all encoding methods produce 32 bytes
  printStep(8, 'Summary - All Encoding Methods')

  printInfo('ABIAddressType accepts:')
  printInfo('  1. Address string (base32 format, 58 chars) -> extracts public key')
  printInfo('  2. Uint8Array (32 bytes) -> uses directly')
  printInfo('  3. Address object -> extracts publicKey property')

  printInfo('\nAll methods produce exactly 32 bytes (no length prefix):')
  printInfo(`  From string:  ${addressType.encode(sampleAddressString).length} bytes`)
  printInfo(`  From Uint8Array: ${addressType.encode(rawPublicKey).length} bytes`)
  printInfo(`  From Address: ${addressType.encode(addressObject).length} bytes`)

  printInfo('\nDecode always returns base32 address string (58 chars)')

  printSuccess('ABI Address Type example completed successfully!')
}

main()

ABI Address Type

Description

Prerequisites

Run This Example

Code

Other examples in ABI Encoding