float_binary_conversion.js

const BYTE = 8;
const BITS = 64;
const SEGMENTS = 8;
const SEGMENT = BITS / SEGMENTS;
const METHODS_MAP = {
  8: ['getUint8', 'setUint8', 'getInt8', 'setInt8'],
  16: ['getUint16', 'setUint16', 'getInt16', 'setInt16'],
  32: ['getUint32', 'setUint32', 'getInt32', 'setInt32'],
};
const [
  MAP_GET_U,
  MAP_SET_U,
  MAP_GET_I,
  MAP_SET_I,
] = [0, 1, 2, 3];
const USE_UNSIGNED = false;
const MAP_GET = USE_UNSIGNED ? MAP_GET_U : MAP_GET_I;
const MAP_SET = USE_UNSIGNED ? MAP_SET_U : MAP_SET_I;

const float2bits = (num) => {
  const buffer = new ArrayBuffer(BITS/BYTE);
  const view = new DataView(buffer);
  view.setFloat64(0, num);
  const max16i = 2 ** SEGMENT;
  const bits = [];
  for (let i = 0; i < SEGMENTS; ++i) {
    const u16 = view[METHODS_MAP[SEGMENT][MAP_GET]](i);
    let b = max16i >> 1;
    while (b) {
      bits.push(u16 & b ? 1 : 0);
      b >>= 1;
    }
  }
  return bits;
};