How in JS check if array of objects contains one object?

Question

I have this code:

 var users = [];
users.push({
 username: "admin",
 password: "admin"
});
this.showAllUsers = function() {
 console.log(users);
};
this.addUser = function(user) {
 if('username' in user && 'password' in user) {
 users.push({
 username: user.username,
 password: user.password
 })
 }
 else {
 throw "Invalid object";
 }
};
this.isExist = function(user) {
 console.log(users.indexOf({
 username: "admin",
 password: "admin"
 }));
};

Why console log prints all the time -1 ? Users array contains array with object with property username: "admin: and password: "admin".

• James Thorpe: Just a note - if you're intending to put passwords in some client side code, you may want to rethink what you're doing.
• epascarello: You need to loop and check each property.
• Lee: you can't simply check object equality in javascript. stackoverflow.com/questions/201183/…

Answer 1

The indexOf method uses strict equals (===). When you use {foo: bar}, you create a new (unique) object that will not evaluate strictly equal to anything already in the array.

What you should do is iterate through the array and use a function to compare each object using deep equality. Simply, you could use something like:

function match(arr, ref) { // Take an array and a reference object
 return arr.filter(function (cur) { // Select any items in the array...
 return Object.keys(ref).every(function (key) { // Where all keys...
 return ref[key] === cur[key]; // Have the same value in the item and reference
 });
 });
}

Answer 2

Take a look here indexOf.
And remember that managing passwords on the client side is security flaw.

Answer 3

this.isExist = function(user) {
 console.log(users.indexOf({
 username: "admin",
 password: "admin"
 }));
};

The problem here is that you're checking if the users array contains this new object you're creating. Since it's a new object, it's obviously not going to contain it. You need to check to see if the users object contains any object that has a username or password equal to "admin". Maybe something like

this.isExist = function(user) {
 for(var x = 0; x < users.length; x++) {
 var current = users[x];
 if(current.username === user.username && current.password === user.password) {
 return true;
 }
 }
 return false;
};

Or, alternatively, you can simply use Linq.js, which helps a lot with these kind of queries. It's one of my favorite libraries.

https://linqjs.codeplex.com/