case-compare/examples/lodash/original.js

An alternative to vanilla switch

function equalByTag(object, other, tag, bitmask, customizer, equalFunc, stack) {
  switch (tag) {
    case dataViewTag:
      if ((object.byteLength != other.byteLength) ||
          (object.byteOffset != other.byteOffset)) {
        return false;
      }
      object = object.buffer;
      other = other.buffer;

    case arrayBufferTag:
      if ((object.byteLength != other.byteLength) ||
          !equalFunc(new Uint8Array(object), new Uint8Array(other))) {
        return false;
      }
      return true;

    case boolTag:
    case dateTag:
    case numberTag:
      // Coerce booleans to `1` or `0` and dates to milliseconds.
      // Invalid dates are coerced to `NaN`.
      return eq(+object, +other);

    case errorTag:
      return object.name == other.name && object.message == other.message;

    case regexpTag:
    case stringTag:
      // Coerce regexes to strings and treat strings, primitives and objects,
      // as equal. See http://www.ecma-international.org/ecma-262/7.0/#sec-regexp.prototype.tostring
      // for more details.
      return object == (other + '');

    case mapTag:
      var convert = mapToArray;

    case setTag:
      var isPartial = bitmask & COMPARE_PARTIAL_FLAG;
      convert || (convert = setToArray);

      if (object.size != other.size && !isPartial) {
        return false;
      }
      // Assume cyclic values are equal.
      var stacked = stack.get(object);
      if (stacked) {
        return stacked == other;
      }
      bitmask |= COMPARE_UNORDERED_FLAG;

      // Recursively compare objects (susceptible to call stack limits).
      stack.set(object, other);
      var result = equalArrays(convert(object), convert(other), bitmask, customizer, equalFunc, stack);
      stack['delete'](object);
      return result;

    case symbolTag:
      if (symbolValueOf) {
        return symbolValueOf.call(object) == symbolValueOf.call(other);
      }
  }
  return false;
}