improved typing (#25)

Author: jleni

bun.lockb

@@ -41,9 +41,9 @@
     "@ledgerhq/hw-transport-mocker": "^6.28.6",
     "@trivago/prettier-plugin-sort-imports": "^4.3.0",
     "@types/jest": "29.5.12",
-    "@types/node": "^20.12.11",
-    "@typescript-eslint/eslint-plugin": "^7.8.0",
-    "@typescript-eslint/parser": "^7.8.0",
+    "@types/node": "^20.12.12",
+    "@typescript-eslint/eslint-plugin": "^7.9.0",
+    "@typescript-eslint/parser": "^7.9.0",
     "eslint": "^9.2.0",
     "eslint-config-prettier": "^9.1.0",
     "eslint-config-standard-with-typescript": "^39.0.0",

package.json

@@ -15,14 +15,15 @@
  *****************************************************************************/
 import { HARDENED, LedgerError } from './consts'
 import { ResponseError } from './responseError'
+import { BIP32Path } from './types'
 
 /**
  * Serializes a derivation path into a buffer.
  * @param path - The derivation path in string format.
  * @returns A buffer representing the serialized path.
  * @throws {ResponseError} If the path format is incorrect or invalid.
  */
-export function serializePath(path: string, requiredPathLengths?: number[]): Buffer {
+export function serializePath(path: BIP32Path, requiredPathLengths?: number[]): Buffer {
   if (typeof path !== 'string') {
     // NOTE: this is probably unnecessary
     throw new ResponseError(LedgerError.GenericError, "Path should be a string (e.g \"m/44'/461'/5'/0/3\")")
@@ -71,7 +72,7 @@ export function serializePath(path: string, requiredPathLengths?: number[]): Buf
  * @returns The derivation path in string format.
  * @throws {Error} If the array length is not a multiple of 4 or if the array contains invalid values.
  */
-export function numbersToBip32Path(items: number[]): string {
+export function numbersToBip32Path(items: number[]): BIP32Path {
   if (items.length === 0) {
     throw new ResponseError(LedgerError.GenericError, 'The items array cannot be empty.')
   }
@@ -99,7 +100,7 @@ export function numbersToBip32Path(items: number[]): string {
  * @returns The derivation path in string format.
  * @throws {Error} If the buffer length is not a multiple of 4 or if the buffer contains invalid values.
  */
-export function bufferToBip32Path(buffer: Buffer): string {
+export function bufferToBip32Path(buffer: Buffer): BIP32Path {
   if (buffer.length % 4 !== 0) {
     throw new ResponseError(LedgerError.GenericError, 'The buffer length must be a multiple of 4.')
   }

src/bip32.ts

@@ -18,7 +18,7 @@ import { ResponseError } from './responseError'
 
 export class ResponsePayload {
   private offset = 0
-  private internalBuffer: Buffer
+  private readonly internalBuffer: Buffer
 
   constructor(payload: Buffer) {
     this.internalBuffer = payload

src/payload.ts

@@ -77,3 +77,5 @@ export interface ConstructorParams {
   chunkSize: number
   acceptedPathLengths?: number[]
 }
+
+export type BIP32Path = string