wip convert Node Crypto to class

haven't formatted this — will do once contents of class are correct

Use of `satisfies` comes from suggestion in [1].

[1] "Allow specifying interface implements clauses for the static side
of classes": microsoft/TypeScript#33892

Author: lawrence-forooghian

src/platform/nodejs/lib/util/crypto.ts

@@ -112,7 +112,7 @@ var Crypto = (function () {
    * concatenated with the resulting raw ciphertext to construct the "ciphertext"
    * data passed to the recipient.
    */
-  function Crypto() {}
+  class Crypto {
 
   /**
    * Obtain a complete CipherParams instance from the provided params, filling
@@ -123,7 +123,7 @@ var Crypto = (function () {
    * base64-encoded string. May optionally also contain: algorithm (defaults to
    * AES), mode (defaults to 'cbc')
    */
-  Crypto.getDefaultParams = function (params: API.Types.CipherParamOptions) {
+  static getDefaultParams(params: API.Types.CipherParamOptions) {
     var key;
 
     if (!params.key) {
@@ -154,15 +154,15 @@ var Crypto = (function () {
 
     validateCipherParams(cipherParams);
     return cipherParams;
-  };
+  }
 
   /**
    * Generate a random encryption key from the supplied keylength (or the
    * default keyLength if none supplied) as a Buffer
    * @param keyLength (optional) the required keyLength in bits
    * @param callback (optional) (err, key)
    */
-  Crypto.generateRandomKey = function (keyLength?: number, callback?: API.Types.StandardCallback<API.Types.CipherKey>) {
+  static generateRandomKey(keyLength?: number, callback?: API.Types.StandardCallback<API.Types.CipherKey>) {
     if (arguments.length == 1 && typeof keyLength == 'function') {
       callback = keyLength;
       keyLength = undefined;
@@ -175,22 +175,27 @@ var Crypto = (function () {
     generateRandom((keyLength || DEFAULT_KEYLENGTH) / 8, (err, buf) => {
       callback!(err ? ErrorInfo.fromValues(err) : null, buf);
     });
-  };
+  }
 
   /**
    * Internal; get a ChannelCipher instance based on the given cipherParams
    * @param params either a CipherParams instance or some subset of its
    * fields that includes a key
    */
-  Crypto.getCipher = function (params: IGetCipherParams<IV>) {
+  static getCipher(params: IGetCipherParams<IV>) {
     var cipherParams = isInstCipherParams(params) ? params : Crypto.getDefaultParams(params);
 
     var iv = params.iv || generateRandom(DEFAULT_BLOCKLENGTH);
     return {
       cipherParams: cipherParams /* CipherOptions.cipher */,
       cipher: new CBCCipher(cipherParams, iv) /* CipherOptions.channelCipher */,
     };
-  };
+  }
+
+  }
+
+  // TODO sort out
+  // Crypto satisfies ICrypto<IV, InputPlaintext, OutputCiphertext, InputCiphertext, OutputPlaintext>;
 
   const CBCCipher = function CBCCipher(
     this: { algorithm: string; key: NodeCipherKey; iv: IV | null; encryptCipher: NodeCipher; blockLength: number },