Add Tempo token address helper

src/tempo/TokenAddress.ts

@@ -0,0 +1,30 @@
+import * as Address from '../core/Address.js'
+import * as TempoAddress from './TempoAddress.js'
+
+export const prefix = '0x20c000000000000000000000'
+
+/**
+ * Returns whether an address is a TIP-20 token address.
+ *
+ * [TIP-20 Token Standard](https://docs.tempo.xyz/protocol/tip20/overview)
+ *
+ * @example
+ * ```ts twoslash
+ * import { TokenAddress } from 'ox/tempo'
+ *
+ * const isTip20 = TokenAddress.isTip20('0x20c0000000000000000000000000000000000001')
+ * // @log: true
+ * ```
+ *
+ * @param address - Address to check.
+ * @returns Whether the address is a TIP-20 token address.
+ */
+export function isTip20(address: TempoAddress.Address): boolean {
+  const resolved = TempoAddress.resolve(address)
+  Address.assert(resolved, { strict: false })
+  return resolved.toLowerCase().startsWith(prefix)
+}
+
+export declare namespace isTip20 {
+  type ErrorType = Address.assert.ErrorType | TempoAddress.parse.ErrorType
+}

src/tempo/TokenId.test.ts

@@ -1,5 +1,5 @@
 import { Hex } from 'ox'
-import { TokenId } from 'ox/tempo'
+import { TokenAddress, TokenId } from 'ox/tempo'
 import { expect, test } from 'vitest'
 
 test('from', () => {
@@ -29,6 +29,24 @@ test('fromAddress', () => {
   expect(TokenId.fromAddress(tempoAddr)).toBe(1n)
 })
 
+test('fromAddress: invalid address', () => {
+  expect(() =>
+    TokenId.fromAddress('0x20c1000000000000000000000000000000000001'),
+  ).toThrow('invalid tip20 address.')
+})
+
+test('TokenAddress.isTip20', () => {
+  expect(
+    TokenAddress.isTip20('0x20c0000000000000000000000000000000000001'),
+  ).toBe(true)
+  expect(
+    TokenAddress.isTip20('tempox0x20c0000000000000000000000000000000000001'),
+  ).toBe(true)
+  expect(
+    TokenAddress.isTip20('0x20c1000000000000000000000000000000000001'),
+  ).toBe(false)
+})
+
 test('toAddress', () => {
   expect(TokenId.toAddress(0n)).toBe(
     '0x20c0000000000000000000000000000000000000',

src/tempo/TokenId.ts

@@ -3,8 +3,10 @@ import * as Address from '../core/Address.js'
 import * as Hash from '../core/Hash.js'
 import * as Hex from '../core/Hex.js'
 import * as TempoAddress from './TempoAddress.js'
+import * as TokenAddress from './TokenAddress.js'
 
-const tip20Prefix = '0x20c0'
+const tip20Prefix = TokenAddress.prefix
+const tip20PrefixSize = 12
 
 export type TokenId = bigint
 export type TokenIdOrAddress<addressType = Address.Address> =
@@ -55,9 +57,8 @@ export function from(tokenIdOrAddress: TokenIdOrAddress | number): TokenId {
  */
 export function fromAddress(address: TempoAddress.Address): TokenId {
   const resolved = TempoAddress.resolve(address)
-  if (!resolved.toLowerCase().startsWith(tip20Prefix))
-    throw new Error('invalid tip20 address.')
-  return Hex.toBigInt(Hex.slice(resolved, tip20Prefix.length))
+  if (!TokenAddress.isTip20(resolved)) throw new Error('invalid tip20 address.')
+  return Hex.toBigInt(Hex.slice(resolved, tip20PrefixSize))
 }
 
 /**
@@ -84,7 +85,7 @@ export function toAddress(
     return resolved
   }
 
-  const tokenIdHex = Hex.fromNumber(tokenId, { size: 18 })
+  const tokenIdHex = Hex.fromNumber(tokenId, { size: 8 })
   return Hex.concat(tip20Prefix, tokenIdHex)
 }
 

src/tempo/VirtualMaster.ts

@@ -6,9 +6,9 @@ import * as Hash from '../core/Hash.js'
 import * as Hex from '../core/Hex.js'
 import * as VirtualMasterPool from './internal/virtualMasterPool.js'
 import * as TempoAddress from './TempoAddress.js'
+import * as TokenAddress from './TokenAddress.js'
 import * as VirtualAddress from './VirtualAddress.js'
 
-const tip20Prefix = '0x20c000000000000000000000'
 const zeroAddress = '0x0000000000000000000000000000000000000000'
 
 /** A valid salt input for TIP-1022 master registration. */
@@ -680,7 +680,7 @@ function assertValidMasterAddress(address: Address.Address) {
       'Virtual master address cannot itself be a virtual address.',
     )
 
-  if (normalized.startsWith(tip20Prefix))
+  if (TokenAddress.isTip20(address))
     throw new Errors.BaseError(
       'Virtual master address cannot be a TIP-20 token address.',
     )

src/tempo/index.ts

@@ -283,6 +283,12 @@ export * as TempoAddress from './TempoAddress.js'
  * @category Reference
  */
 export * as Tick from './Tick.js'
+/**
+ * TIP-20 token address utilities.
+ *
+ * @category Reference
+ */
+export * as TokenAddress from './TokenAddress.js'
 /**
  * TIP-20 token ID utilities for converting between token IDs and addresses.
  *