order placement doesnt crash

src/blockchain/orderlib.js

@@ -29,12 +29,12 @@ export function newOrder(tokenIn, tokenOut, exchange, fee, amount, amountIsInput
 }
 
 // struct Tranche {
-//     uint64 fraction; // 18-decimal fraction of the order amount which is available to this tranche. must be <= 1
+//     uint64 fraction;
 //     Constraint[] constraints;
 // }
 export function newTranche(amountRatio, constraints) {
     return [
-        BigInt(Math.ceil(amountRatio * 10**18)), // we use ceil to make sure the sum of tranche fractions doesn't round below 1
+        BigInt(Math.min(65535, Math.ceil(amountRatio * 65535))), // we use ceil to make sure the sum of tranche fractions doesn't round below 1
         constraints
     ]
 }