code: function areEqual(a: any, b: any): boolean {
    const aStack = aStackPool.length ? aStackPool.pop() : [];
    const bStack = bStackPool.length ? bStackPool.pop() : [];
    const result = eq(a, b, aStack, bStack);
    aStack.length = 0;
    bStack.length = 0;
    aStackPool.push(aStack);
    bStackPool.push(bStack);
    return result;
  }
docs: Checks if two values are equal. Values may be primitives, arrays, or objects.
  Returns true if both arguments have the same keys and values.
  
  @see http://underscorejs.org
  @copyright 2009-2013 Jeremy Ashkenas, DocumentCloud Inc.
  @license MIT