Add extracted source directory and README navigation

extracted-source/node_modules/@smithy/hash-node/dist-cjs/index.js

@@ -0,0 +1,42 @@
+'use strict';
+
+var utilBufferFrom = require('@smithy/util-buffer-from');
+var utilUtf8 = require('@smithy/util-utf8');
+var buffer = require('buffer');
+var crypto = require('crypto');
+
+class Hash {
+    algorithmIdentifier;
+    secret;
+    hash;
+    constructor(algorithmIdentifier, secret) {
+        this.algorithmIdentifier = algorithmIdentifier;
+        this.secret = secret;
+        this.reset();
+    }
+    update(toHash, encoding) {
+        this.hash.update(utilUtf8.toUint8Array(castSourceData(toHash, encoding)));
+    }
+    digest() {
+        return Promise.resolve(this.hash.digest());
+    }
+    reset() {
+        this.hash = this.secret
+            ? crypto.createHmac(this.algorithmIdentifier, castSourceData(this.secret))
+            : crypto.createHash(this.algorithmIdentifier);
+    }
+}
+function castSourceData(toCast, encoding) {
+    if (buffer.Buffer.isBuffer(toCast)) {
+        return toCast;
+    }
+    if (typeof toCast === "string") {
+        return utilBufferFrom.fromString(toCast, encoding);
+    }
+    if (ArrayBuffer.isView(toCast)) {
+        return utilBufferFrom.fromArrayBuffer(toCast.buffer, toCast.byteOffset, toCast.byteLength);
+    }
+    return utilBufferFrom.fromArrayBuffer(toCast);
+}
+
+exports.Hash = Hash;