export function geohashForLocation()

in packages/geofire-common/src/index.ts [146:197]

• 47 lines of code
• 12 McCabe index (conditional complexity)

export function geohashForLocation(location: Geopoint, precision: number = GEOHASH_PRECISION): Geohash {
  validateLocation(location);
  if (typeof precision !== 'undefined') {
    if (typeof precision !== 'number' || isNaN(precision)) {
      throw new Error('precision must be a number');
    } else if (precision <= 0) {
      throw new Error('precision must be greater than 0');
    } else if (precision > 22) {
      throw new Error('precision cannot be greater than 22');
    } else if (Math.round(precision) !== precision) {
      throw new Error('precision must be an integer');
    }
  }

  const latitudeRange = {
    min: -90,
    max: 90
  };
  const longitudeRange = {
    min: -180,
    max: 180
  };
  let hash = '';
  let hashVal = 0;
  let bits = 0;
  let even: number | boolean = 1;

  while (hash.length < precision) {
    const val = even ? location[1] : location[0];
    const range = even ? longitudeRange : latitudeRange;
    const mid = (range.min + range.max) / 2;

    if (val > mid) {
      hashVal = (hashVal << 1) + 1;
      range.min = mid;
    } else {
      hashVal = (hashVal << 1) + 0;
      range.max = mid;
    }

    even = !even;
    if (bits < 4) {
      bits++;
    } else {
      bits = 0;
      hash += BASE32[hashVal];
      hashVal = 0;
    }
  }

  return hash;
}