feat: contract helper to extract event

Author: chamrun

src/contract-helper/index.ts

@@ -0,0 +1,29 @@
+import { Slice } from '@ton/core'
+
+const CHANGE_NUMBER_NOTIFICATION_EVENT_CODE = 0x5c690c2f
+
+
+
+const hexToString = (hexString: string): string => {
+ const hex = hexString.toString()
+ let resultString = ''
+ for (let i = 0; i < hex.length; i += 2) {
+ resultString += String.fromCharCode(parseInt(hex.slice(i, i + 2), 16))
+ }
+ return resultString
+}
+
+export const extractEventFromMessage = (message: Slice): { event: number } | { error: string } => {
+ const operationCode = message.loadUint(32)
+ let event = 0
+
+ if (operationCode === CHANGE_NUMBER_NOTIFICATION_EVENT_CODE) {
+ const eventString = hexToString(message.loadUintBig(13 * 8).toString(16)!)
+ if (eventString === 'ChangedNumber') {
+ event = message.loadUint(8)
+ } else {
+ return { error: 'Unsupported slice format' }
+ }
+ }
+ return { event }
+}