Merge pull request #12 from keepkey/issue-#4/utility-for-bip32-to-add…

…ressn

Utility for converting bip32 to addressN closes #4

src/utils.test.ts

@@ -54,4 +54,25 @@ describe('utils', () => {
       expect(utils.fromHexString('!')).toEqual(new Uint8Array([0]))
     })
   })
+
+  describe('bip32ToAddressNList', () => {
+    test('formats return value correctly', () => {
+      expect(utils.bip32ToAddressNList(`m/44'/60'/0'/0/0`)).toEqual([ -2147483604, -2147483588, -2147483648, 0, 0 ])
+    })
+    test('will always return an array if the path looks valid', () => {
+      expect(utils.bip32ToAddressNList(`m/`)).toEqual([])
+    })
+    test('throws when given an incorrect bip32 path', () => {
+      expect(() => utils.bip32ToAddressNList(`/44'/60'/0'/0/0`)).toThrow()
+    })
+  })
+
+  describe('bip32Like', () => {
+    test('returns true if path is valid', () => {
+      expect(utils.bip32Like(`m/`)).toEqual(true)
+    })
+    test('returns false otherwise', () => {
+      expect(utils.bip32Like(`/44'/60'/0'/0/0`)).toEqual(false)
+    })
+  })
 })

src/utils.ts

@@ -60,3 +60,18 @@ export function arrayify (value: string): Uint8Array {
     return new Uint8Array(result)
   }
 }
+
+const harden = 0x80000000
+export function bip32ToAddressNList (address: string): number[] {
+  if (!bip32Like(address)) throw new Error('Unrecognized bip32 path')
+  address = address.slice(1, address.length)
+  return address.split('/').filter(part => part.length).map(part => {
+    const insertHarden = part.indexOf(`'`) > -1
+    const num = parseFloat(part)
+    return insertHarden ? harden | num : num
+  })
+}
+
+export function bip32Like (address: string): boolean {
+  return address.slice(0, 2) === 'm/'
+}