Add hashing function (based on djb2) to util #2027

src/util/hash.js

@@ -0,0 +1,36 @@
+let hashIterableInts = function( iterator, seed = 5381 ){ // djb2/string-hash
+  let hash = seed;
+  let entry;
+
+  for( ;; ){
+    entry = iterator.next();
+
+    if( entry.done ){ break; }
+
+    hash = (hash * 33) ^ entry.value;
+  }
+
+  return hash >>> 0;
+};
+
+let hashString = function( str, seed ){
+  let entry = { value: 0, done: false };
+  let i = 0;
+  let length = str.length;
+
+  let iterator = {
+    next(){
+      if( i < length ){
+        entry.value = str.charCodeAt(i++);
+      } else {
+        entry.done = true;
+      }
+
+      return entry;
+    }
+  };
+
+  return hashIterableInts( iterator, seed );
+};
+
+module.exports = { hashIterableInts, hashString };

src/util/index.js

@@ -162,7 +162,8 @@ util.setPrefixedProperty = function( obj, propName, prefix, value ){
   require( './regex' ),
   require( './strings' ),
   require( './timing' ),
-  require( './sort' )
+  require( './sort' ),
+  require( './hash' )
 ].forEach( function( req ){
   util.extend( util, req );
 } );