javascript check if a key value exists in 2 JSON objects at once

Question

I have 2 JSON objects and want to check if a value from the first one appears anywhere in the second one, and if it does, push it into an array. I've tried to write a for loop to do this, but somehow I can't seem to get it right.

Can anybody point out what I'm doing wrong?

 var JSON1 = [{ "1": "1", "2": "2" }, { "1": "3", "2": "4" }]; var JSON2 = [{ "1": "1", "2": "2" }, { "1": "3", "2": "4" }]; var matching = []; for (var key in JSON1) { if(JSON2[.hasOwnProperty(JSON1[key].1) ) { matching.push(JSON1[key].1); } } console.log(matching); 

Answer 1

you can compare both by there values

var JSON1 = [{
    "1": "1",
        "2": "2"
}, {
    "1": "3",
        "2": "4"
}];

var JSON2 = [{
    "1": "1",
        "2": "2"
}, {
    "1": "3",
        "2": "4"
}];

var matching = [];



for(x in JSON1) {
  for(y in JSON1[x]){
    if(JSON1[x][y] ==  JSON2[x][y]){
       matching.push(JSON1[x][y]);
       }
  }
}



console.log(matching);

Answer 2

Note: For numbers as key you should use obj[number] not obj.number .

 var JSON1 = [{ "1": "1", "2": "2" }, { "1": "3", "2": "4" }]; var JSON2 = [{ "1": "1", "2": "2" }, { "1": "3", "2": "4" }]; var matching = []; for (var key in JSON1) { for(var k in JSON1[key]){ if(key in JSON2 && k in JSON2[key] && JSON1[key][k] == JSON2[key][k]) { matching.push(JSON1[key][k]); } } } console.log(matching);