[UI] Added quick String.hashCode function.

This is needed in several places in the code where we need to compare if
two strings differ, but either the strings are too long (e.g. content of
large files) or we don't want to pass the original values (e.g.
credentials, session tokens etc.).

platypush/backend/http/webapp/src/utils/Text.vue

@@ -1,4 +1,21 @@
 <script>
+
+// From https://stackoverflow.com/questions/7616461/generate-a-hash-from-string-in-javascript
+String.prototype.hashCode = function(seed = 0) {
+  let h1 = 0xdeadbeef ^ seed, h2 = 0x41c6ce57 ^ seed;
+  for(let i = 0, ch; i < this.length; i++) {
+    ch = this.charCodeAt(i);
+    h1 = Math.imul(h1 ^ ch, 2654435761);
+    h2 = Math.imul(h2 ^ ch, 1597334677);
+  }
+
+  h1  = Math.imul(h1 ^ (h1 >>> 16), 2246822507);
+  h1 ^= Math.imul(h2 ^ (h2 >>> 13), 3266489909);
+  h2  = Math.imul(h2 ^ (h2 >>> 16), 2246822507);
+  h2 ^= Math.imul(h1 ^ (h1 >>> 13), 3266489909);
+  return 4294967296 * (2097151 & h2) + (h1 >>> 0);
+};
+
 export default {
   name: "Text",
   methods: {