Javascript gets corresponding key / value from object

Question

I have an object that might look like this:

var nicknames = []
nicknames.push({id:"100", name:"john", id2:"200", name2:"max"});

but the object might look like this:

nicknames.push({id:"200", name:"max", id2:"100", name2:"john"});

therefore, the key and values ​​can be switched.

How can I get the name and id of "john" and "100" if you specify the name "max" or id "200" ?

Answer 1

var found_name, found_id;
for(var i = 0; i < nicknames.length; i++) {
    var nn = nicknames[i];
    if (nn.name == "max" || nn.id = "200") {
        found_name = nn.name2;
        found_id = nn.id2;
        break;
    } else if (nn.name2 == "max" || nn.id2 = "200") {
        found_name = nn.name;
        found_id = nn.id;
        break;
    }
}

Answer 2

It may be useful for you.

var nicknames= [ {id:"100", nickname:"John"}, {id:"200", nickname:"Michael"} ];

function getByName(arr, value) {
   for (var i=0, iLen=arr.length; i<iLen; i++) {
      if (arr[i].nickname == value) return arr[i];
   }
}

var object = getByName(nicknames, "John");

// Will show '100'
alert(object.id); 

You can see it in action here: http://jsfiddle.net/b1yL28at/

Answer 3

, , , ,

var nicknames = []

nicknames.push({
    id: "100",
    name: "john",
    id2: "200",
    name2: "max"
});

var idIndex = {},
    nameIndex = {};

nicknames.forEach(function(currentNickName) {

    idIndex[currentNickName.id] = {
        id: currentNickName.id2,
        name: currentNickName.name2
    };
    idIndex[currentNickName.id2] = {
        id: currentNickName.id,
        name: currentNickName.name
    };

    nameIndex[currentNickName.name] = {
        id: currentNickName.id2,
        name: currentNickName.name2
    };
    nameIndex[currentNickName.name2] = {
        id: currentNickName.id,
        name: currentNickName.name
    };

});

console.log(nameIndex, idIndex);

{ john: { id: '200', name: 'max' }, max: { id: '100', name: 'john' } }
{ '100': { id: '200', name: 'max' }, '200': { id: '100', name: 'john' } }

,

console.log(nameIndex["max"]);
// { id: '100', name: 'john' }
console.log(nameIndex["john"]);
// { id: '200', name: 'max' }
console.log(idIndex["100"]);
// { id: '200', name: 'max' }
console.log(idIndex["200"]);
// { id: '100', name: 'john' }

Answer 4

, .

, ( ) , id-name . , .

, , , , : id/names; ( - , ).

Answer 5

, , , :

var nicknames = [{id:"100", name:"john", id2:"200", name2:"max"},
                 {id:"300", name:"tim", id2:"400", name2:"fred"}];

function getOther(nameOrId) {
  var nickname;

  for (var i=0, iLen=nicknames.length; i<iLen; i++) {
    nickname = nicknames[i];

    if (nickname.id == nameOrId || nickname.name == nameOrId) {
      return [nickname.id2, nickname.name2];
    }
    if (nickname.id2 == nameOrId || nickname.name2 == nameOrId) {
      return [nickname.id, nickname.name];
    }
  }
}

console.log(getOther('max')); // ["100", "john"]

console.log(getOther('100')); // ["200", "max"]

console.log(getOther('400')); // ["300", "tim"]

It simply looks for a match with the name or identifier in a pair of aliases, and if it finds one, it returns the other. This can be made more general.

If you want to keep Douglas Crockford happy and avoid the loop using the ES5 function, then:

function getOther(nameOrId) {
  var result;

  nicknames.some(function (nickname) {
    if (nickname.id == nameOrId || nickname.name == nameOrId) {
      return result = [nickname.id2, nickname.name2];
    }
    if (nickname.id2 == nameOrId || nickname.name2 == nameOrId) {
      return result = [nickname.id, nickname.name];
    }
  });
  return result;
}

But I do not see the point, this is exactly the same number of lines of code and clearer (IMHO, of course).