docs: add v0.30 migration guide

website/docs/migrations/migrate-to-v0.30.md

@@ -0,0 +1,75 @@
+# Migrate to Lumos v0.30
+
+## BREAKING: Buffer replaced by Uint8Array
+
+**Lumos can now run in browsers without any extra configs / polyfills with vite, webpack or create-react-app.**
+
+### `Buffer` was return type
+
+Methods / functions used to return a `Buffer` now returns a `Uint8Array`, e.g. In `@ckb-lumos/hd`
+
+```diff
+- export function privateToPublic(privateKey: Buffer | HexString): Buffer | HexString
++ export function privateToPublic(privateKey: Uint8Array | HexString): Uint8Array | HexString
+
+// @ckb-lumos/hd/mnemonic
+- export function mnemonicToSeedSync(mnemonic = "", password = ""): Buffer
++ export function mnemonicToSeedSync(mnemonic = "", password = ""): Uint8Array
+
+- export function mnemonicToSeed(mnemonic = "", password = ""): Promise<Buffer>
++ export function mnemonicToSeed(mnemonic = "", password = ""): Promise<Uint8Array>
+```
+
+You can use the `hexify` method from `@ckb-lumos/lumos/codec` to replace `buffer.toString('hex')`
+
+```diff
+- "0x" + privateToPublick(privKey).toString('hex')
++ hexify(privateToPublic(privKey))
+```
+
+**Notice:** `hexify` returns `HexString` which starts with `'0x'` while `buffer.toString('hex')` result has **no** `'0x'` prefix.
+
+Same for `@ckb-lumos/hd/KeyStore`
+
+```diff
+export default class Keystore {
+  ...
+- derivedKey(password: string): Buffer
++ derivedKey(password: string): Uint8Array
+  ...
+}
+```
+
+### `Buffer` was parameter type
+
+You can still pass in `Buffer` because `Buffer` is a subclass of `Uint8Array`, but using `Uint8Array` is recomended.
+
+`@ckb-lumos/hd/KeyChain`
+
+```diff
+export default class Keychain {
+  ...
+- constructor(privateKey: Buffer, chainCode: Buffer)
++ constructor(privateKey: Uint8Array, chainCode: Uint8Array)
+  ...
+- hash160(data: Buffer): Buffer
++ hash160(data: Uint8Array): Uint8Array
+}
+```
+
+`@ckb-lumos/hd/KeyStore`
+
+```diff
+export default class Keystore {
+  ...
+  static create(
+      extendedPrivateKey: ExtendedPrivateKey,
+      password: string,
+-     options: { salt?: Buffer; iv?: Buffer } = {}
++     options: { salt?: Uint8Array; iv?: Uint8Array } = {}
+    ): Keystore
+  ...
+- static mac(derivedKey: Buffer, ciphertext: Buffer): HexStringWithoutPrefix
++ static mac(derivedKey: Uint8Array, ciphertext: Uint8Array): HexStringWithoutPrefix
+}
+```