Function castToBigInt

src/parseTools.mjs:280–295

(x)

// XXX Make all i64 parts signed

function castToBigInt(x) {
  // Micro-size-optimization: if x is an integer literal, then we can append
  // the suffix 'n' instead of casting to BigInt(), to get smaller code size.
  var n = Number(x);
  if (Number.isInteger(n) && isFinite(n)) {
    // NOTE: BigInt(316059037807746200000) != 316059037807746200000n
    // i.e. constructing numbers with BigInt()s is subject to rounding, if
    // the input value cannot be exactly represented as a 64-bit double.
    // Currently the test suite depends on this rounding behavior, so only
    // apply this literal optimization to safe integers for now.
    if (Math.abs(n) < Number.MAX_SAFE_INTEGER) {
      return `${x}n`;
    }
  }
  return `BigInt(${x})`;
}


// Splits a number (an integer in a double, possibly > 32 bits) into an i64