Optimize getRandomChar and produce

Author: omgovich

README.md

@@ -4,8 +4,8 @@
 
 A tiny memorable password generator
 
-- **Fast**: 16 times faster than `password-generator`
-- **Small**: 342 bytes (minified and gzipped)
+- **Fast**: 600 times faster than `password-generator`
+- **Small**: 334 bytes (minified and gzipped)
 - **Safe**: Uses [cryptographically strong random API](https://nodejs.org/api/crypto.html) instead of `Math.random`
 - **No dependencies**
 - Supports Node.js and browsers

index.js

@@ -37,25 +37,25 @@ const getRandomSyllable = ({
   return syllable;
 };
 
-const getRandomChar = stack => {
-  return stack.charAt(random(stack.length));
-};
+const getRandomChar = stack => stack[random(stack.length)];
 
 const produce = (number, callback) => {
-  let result = "";
-  for (let index = 0; index < number; index++) result += callback(index);
+  for (var index = 0, result = ""; index < number; index++) {
+    result += callback(index);
+  }
+
   return result;
 };
 
 let buffer = [];
 let bufferSize = 0xffff;
-let bufferIndex = bufferSize + 1;
+let bufferIndex = bufferSize;
 
 const random = limit => {
-  if (++bufferIndex > bufferSize) {
+  if (bufferIndex >= bufferSize) {
     buffer = getRandomValues(bufferSize);
     bufferIndex = 0;
   }
 
-  return buffer[bufferIndex] % limit;
+  return buffer[bufferIndex++] % limit;
 };

test/benchmark.js

@@ -11,7 +11,7 @@ const libraries = [
     name: "omgopass",
     browser: true,
     node: true,
-    size: 342,
+    size: 334,
     generate: () => omgopass()
   },
   {