odd.js

function lemonthink() {
   let buf = new ArrayBuffer(4);
   let lemon = new Int32Array(buf);
   let think = new Float32Array(buf);

   lemon[0] = 0x7F800001; // A NaN that's not the normal JS NaN
   think[0] = think[0]; // When interpreted, JS sees the (different to normal) NaN and replaces it with a normal NaN.  Compiled JS doesn't modify the value.
   return lemon[0];
}
console.log(lemonthink()); // 0x7fc00001, 2143289345
for(let i = 0; i < 20000; i++) lemonthink();
console.log(lemonthink()); // 0x7f800001, 2139095041