Using a value to compare against an array of objects to return a different value within that object?

would it be possible to use .map over this array, and then use this id to return to me the one object that contains and matches this id?

No, it would not be possible (or its usage wouldn't be the proper one) because map

creates a new array with the results of calling a provided function on every element in the calling array

In this case it would create an array with the properties createdAt instead of objects with all the properties (including the id which is necessary to be checked). So you could not pick up the correct object based on the id property.

Instead use find, which

returns the value of the first element in the array that satisfies the provided testing function. Otherwise undefined is returned

Like this:

var obj = array.find(o => o.id === "c2a6e78d2bc34cffb08d6e17a5631467");

Now in obj you have the object with the id equals to c2a6e78d2bc34cffb08d6e17a5631467. You can check if the object is not undefined (it was found) and then access its properties as you wish.

console.log(obj ? obj.createdAt : "not found");

var array = [{
    id: "c2a6e78d2bc34cffb08d6e17a5631467",
    createdAt: '2017-01-02'
  },
  {
    id: "some-other-id",
    createdAt: '2017-01-03'
  },
  {
    id: "some-other-id-2",
    createdAt: '2017-01-03'
  },
];

var obj = array.find(o => o.id === "c2a6e78d2bc34cffb08d6e17a5631467");
console.log(obj ? obj.createdAt : "not found");