Format bits on a JS number to a string

formatBits.ts

// Applying this mask shaves off any floating point components of the numbers.
const MASK32 = 4294967295; // = Math.pow(2, 32) - 1, or 32 ones.

function formatBits(num: number) {
    const out : string[] = [];
    for (let bit = 31; bit >= 0; bit--) {
      out.push(num & (1 << bit) ? "1" : "0");
      if (bit % 8 === 0) out.push(" ");
    }
    out.push(` : ${num & MASK32}`);
    return out.join('');
}