Question

Is it possible to select certain data in a JSON Object using other data in the same JSON Object. Similar to MySQL. For example:

myObj = {"elements" : [ { "name" : "Hydrogen", "symbol" : "H" }, { "name" : "Silver", "symbol" : "Ag" }]};

I want to select “Hydrogen” where the symbol is “H”. Instead of having to put in something like this:

document.getElementByID("TEST").innerHTML = myObj.elements[0].name;

Thank you in advance.

Answer 1

You could define a function to do it for you.

document.getElementByID("TEST").innerHTML = findNameBySymbol(myObj.elements, 'H');

function findNameBySymbol(elements, symbol) {
  for (var i = 0; i < elements.length; i += 1) {
    if (elements[i].symbol === symbol) {
      return elements[i].name;
    }
  }
}

Better yet, if you have any control over the structure of the data, you could structure it like this:

myObj = {"H": "Hydrogen", "Ag": "Silver"};

Then a lookup is as simple as myObj['H'].