function shallowDiffers(a, b) {
	for (let i in a) if (i !== '__source' && !(i in b)) return true;
	for (let i in b) if (i !== '__source' && a[i] !== b[i]) return true;
	return false;
}
Check if two objects have a different shape
@param {object} a
@param {object} b
@returns {boolean}