Watch service

watch.js

function Watch (obj, scheme, handler, pathOriginal = [], _obj = {}) {
	scheme.forEach(fieldName => {
		const path = pathOriginal.map(e => e);
		if (typeof fieldName === 'string') {
			path.push(fieldName);
			if (['string', 'number', 'boolean'].indexOf(typeof obj[fieldName]) !== -1 || obj[fieldName] === null) {
				_obj[fieldName] = obj[fieldName];
				delete obj[fieldName];
				Object.defineProperty(obj, fieldName, {
					  enumerable: true
					, get: () => _obj[fieldName]
					, set: newValue => {
						const oldValue = _obj[fieldName];
						_obj[fieldName] = newValue;
						handler(path, newValue, oldValue);
					}
				});
			} else if (obj[fieldName] instanceof Array) {
				_obj[fieldName] = obj[fieldName];
				delete obj[fieldName];
				obj[fieldName] = new Proxy(_obj[fieldName], {
					set: function (target, property, value) {
						if (property === 'length') return true;
						target.push(value);
						handler(path, newValue, oldValue);
						return true;
					}
				});
			}
		} else if ((typeof fieldName === 'object') && !(fieldName instanceof Array)) {
			Object.keys(fieldName).forEach(_fieldName => {
				path.push(_fieldName);
				Watch(obj[_fieldName], fieldName[_fieldName], handler, path, _obj[_fieldName] = {})
			});
		}
	});
}