export function deepAssign(to, ...rest) {
	let updated = false;
	for (let src of rest) {
		for (let prop in src) {
			const value = src[prop];
			const oldValue = to[prop];
			if (typeof value === 'object' && !Array.isArray(value)) {
				if (typeof oldValue !== 'object') {
					to[prop] = {};
					updated = true;
				}
				updated = deepAssign(to[prop], value) || updated;
			} else if (value === undefined && to[prop] !== undefined) {
				delete to[prop];
			} else if (value !== oldValue) {
				updated = true;
				to[prop] = value;
			}
		}
	}
	return updated;
}

export const pouchDocHash = d => (isObject(d) ? `${d._id}:${d._rev}` : d);
export const pouchDocArrayHash = arr =>
	Array.isArray(arr) ? arr.map(pouchDocHash).join('?') : arr;

export function isObject(obj) {
	return typeof obj === 'object' && !Array.isArray(obj) && obj !== null;
}