-1

This is what I am trying.

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) { 
  return names.indexOf(val) >= 0;
});
alert(isSuperset);

It returns false instead of true. Where I am going wrong.

Ram
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    Even that question was closed, and it included an example: http://stackoverflow.com/q/14130104/218196 . Please learn [ask] a proper question. But basically, all you need to do is apply http://stackoverflow.com/q/237104/218196 repeatedly. – Felix Kling Mar 17 '16 at 15:21
  • This sounds like an [XY problem](http://meta.stackexchange.com/questions/66377/what-is-the-xy-problem). – amphetamachine Mar 17 '16 at 16:52

2 Answers2

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/

Andy
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shashanka n
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  • @Andy Thats because OP's code originally constructs an array of names alone and then proceeded to check if one was a superset of another! You should ideally check for properties which are unique aka id's. `psno` seems to be such an element. I dont see why you'd need to check both the id AND name when checking for the id will suffice(if `psno` is unique, that is. Im assuming this though OP's `object1` and `object2` both have the same `psno`). Aside from this, I do not see OP asking to check for `psno` anywhere in his question. There was a mistake in his code, and I simply corrected it. – shashanka n Mar 17 '16 at 15:40
  • Thanks Andy and Shashanka, Both the answers work perfectly but this one seems easy for me. – Ram Mar 18 '16 at 05:49
1

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

Andy
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