Question

if we have a javascript object

var calories = { apple:200, pear:280, banana:300, peach:325 }

what is best way to find the (first) fruit that has 280 calories?

could Object.getOwnPropertyNames(calories).forEach... but there should be a better way.

For example, I was thinking of Array.prototype.indexOf() which does the same thing for an Array.

Answer 1

Linear search using for..in construct:

var fruit = null;

for (var prop in calories) {

  if (calories[prop] == 280) {

    fruit = prop;
    break;
  }
}