sort alphabetically javascript array of object based on property code example

Example: sort array of objects by string property value

function compareFirstNames( a, b ) {
  if ( a.first_name < b.first_name ){
    return -1;
  }
  if ( a.first_name > b.first_name ){
    return 1;
  }
  return 0;
}

var people =[
    {"first_name":"Carol", "age":29},
    {"first_name":"Anna", "age":32},
    {"first_name":"Bob", "age":32}
];

people.sort( compareFirstNames ); //people is now sorted by first name from a-z