add eth.fromScript

Author: canonbrother

packages/jellyfish-address/__tests__/eth.test.ts

@@ -1,4 +1,4 @@
-import { OP_CODES } from '@defichain/jellyfish-transaction'
+import { OP_CODES, Script } from '@defichain/jellyfish-transaction'
 import { Eth } from '../src'
 
 const keypair = {
@@ -21,3 +21,25 @@ it('should return undefined script for invalid eth address', () => {
   const evmScript = Eth.fromAddress('0xabc123')
   expect(evmScript).toStrictEqual(undefined)
 })
+
+it('should convert evm script to address', () => {
+  const script: Script = {
+    stack: [
+      OP_CODES.OP_16,
+      OP_CODES.OP_PUSHDATA_HEX_BE(keypair.evmAddr.substring(2))
+    ]
+  }
+  const evmAddress = Eth.fromScript(script)
+  expect(evmAddress).toStrictEqual(keypair.evmAddr.substring(2))
+})
+
+it('should return undefined address for invalid evm script', () => {
+  const script: Script = {
+    stack: [
+      OP_CODES.OP_0,
+      OP_CODES.OP_PUSHDATA_HEX_BE(keypair.evmAddr.substring(2))
+    ]
+  }
+  const evmAddress = Eth.fromScript(script)
+  expect(evmAddress).toStrictEqual(undefined)
+})

packages/jellyfish-address/src/eth.ts

@@ -1,11 +1,17 @@
-import { OP_CODES, Script } from '@defichain/jellyfish-transaction'
+import { OP_CODES, OP_PUSHDATA, Script } from '@defichain/jellyfish-transaction'
 
 function validateAddress (address: string): boolean {
   // https://github.com/ethers-io/ethers.js/blob/5210b68a7837654c6b84207a45e1e573d9472d1a/src.ts/address/address.ts#L123
   const regex: RegExp = /^0x[a-fA-F0-9]{40}$/gm
   return regex.test(address)
 }
 
+function validateScript (script: Script): boolean {
+  return script.stack.length === 2 &&
+    script.stack[0].type === OP_CODES.OP_16.type &&
+    script.stack[1].type === 'OP_PUSHDATA' && (script.stack[1] as OP_PUSHDATA).length() === 20
+}
+
 export const Eth = {
   /**
    * @param {string} address to convert into Script
@@ -21,5 +27,19 @@ export const Eth = {
         OP_CODES.OP_PUSHDATA_HEX_BE(address.substring(2))
       ]
     }
+  },
+
+  /**
+   * EVM Script is LE in DVM, revert back to BE as what Ethereum behave
+   *
+   * @param {Script} script to convert into address
+   * @returns {string} address parsed from script
+   */
+  fromScript (script: Script): string | undefined {
+    if (!validateScript(script)) {
+      return undefined
+    }
+    const { hex } = (script.stack[1] as OP_PUSHDATA)
+    return Buffer.from(hex, 'hex').reverse().toString('hex')
   }
 }