Wilddog: 检测用户数据是否存在

wilddog_detect_data.js

function go() {
	var userId = prompt('Username?', 'Guest');
	checkIfUserExists(userId);
}

var USERS_LOCATION = 'https://<your-appid>.wilddogio.com//users';

function userExistsCallback(userId, exists) {
	if (exists) {
		alert('user ' + userId + ' exists!');
	} else {
		alert('user ' + userId + ' does not exist!');
	}
}

// Tests to see if /users/<userId> has any data. 
function checkIfUserExists(userId) {
	var usersRef = new Wilddog(USERS_LOCATION);
	usersRef.child(userId).once('value', function(snapshot) {
		var exists = (snapshot.val() !== null);
		userExistsCallback(userId, exists);
	});
}