Fix - check bigint only if first entry had it

Author: linev

modules/rntuple.mjs

@@ -1137,14 +1137,27 @@ class TDrawSelectorTuple extends TDrawSelector {
    /** @summary Returns true if field can be used as array */
    isArrayBranch(/* tuple, br */) { return false; }
 
+   /** @summary Begin of processing */
+   Begin(tree) {
+      super.Begin(tree);
+      this._first_entry = true;
+      this._has_bigint = false;
+   }
+
    /** @summary Process entry */
    Process(entry) {
-      for (let n = 0; n < this.numBranches(); ++n) {
-         const name = this.nameOfBranch(n);
-         if (typeof this.tgtobj[name] === 'bigint')
-            this.tgtobj[name] = Number(this.tgtobj[name]);
+      if (this._first_entry || this._has_bigint) {
+         for (let n = 0; n < this.numBranches(); ++n) {
+            const name = this.nameOfBranch(n);
+            if (typeof this.tgtobj[name] === 'bigint') {
+               this.tgtobj[name] = Number(this.tgtobj[name]);
+               this._has_bigint = true;
+            }
+         }
       }
 
+      this._first_entry = false;
+
       super.Process(entry);
    }