Check if an array of object is subset of another array of object [closed]

Answer 1

Thats because you're not doing .name when checking .indexOf

var object1 = {
  name: 'one',
  psno: '34'
};
var object2 = {
  name: 'two',
  psno: '34'
};
var object3 = {
  name: 'three',
  psno: '345'
};
var arr1 = [object1, object2, object3];
var arr2 = [object1, object2];
// solution
var names = arr1.map(function(obj) {
  return obj.name;
});
var isSuperset = arr2.every(function(val) {
//Ive changed this line!
  return names.indexOf(val.name) >= 0;
});
alert(isSuperset);

JS Fiddle here: https://jsfiddle.net/waqmafsa/

Answer 2

Here's a method that checks that all key/values in the objects match.

// creates a hash for each object
// e.g. "name|one|psno|34"
function hash(obj) {
  return Object.keys(obj).reduce(function(p, c) {
    return p.concat([c, obj[c]].join('|'));
  }, []).sort().join('|');
}

// returns a hashed object
function hashObject(obj) {
  return hash(obj);
}

// returns a function that checks to see
// if an element is in the array
function within(arr) {
  return function (el) {
    return arr.indexOf(el) > -1;
  }
}

// performs the check    
function check(arr1, arr2) {
  if (arr1.length < arr2.length) return false;
  var hashedArr1 = arr1.map(hashObject);
  return arr2.map(hashObject).every(within(hashedArr1));
}

var issubset = check(arr1, arr2);

DEMO