How to delete a javascript object item by value?

Question

Take, for instance, the following object:

var fruits = {
    "red" : "apple",
    "blue" : "blueberry",
    "yellow" : "banana"
}

I know I can use delete fruits["red"] to remove it by the key name, but how could I delete the object item by the fruit name?

Answer 1

Have you tried something like this?

function deleteByValue(val) {
    for(var f in fruits) {
        if(fruits[f] == val) {
            delete fruits[f];
        }
    }
}

And as per Rocket's comment, you might want to check hasOwnProperty to make sure you aren't deleting members of the object's prototype:

function deleteByValue(val) {
    for(var f in fruits) {
        if(fruits.hasOwnProperty(f) && fruits[f] == val) {
            delete fruits[f];
        }
    }
}

Answer 2

var key = null;
for (var k in fruits){
  if (fruits[k] === 'apple'){
    key = k;
    break;
  }
}
if (key != null)
  delete fruits[key];

Iterate over the object finding the corresponding key, then remove it (if found).

Answer 3

Don't know if this is efficient in terms of processing but using filter you can get this done in three lines:

var fruits = {
    "red" : "apple",
    "blue" : "blueberry",
    "yellow" : "banana"
}

var appleless_keys = Object.keys(fruits).filter(this_fruit => fruits[this_fruit] !== "apple");
appleless_obj = {};
appleless_keys.forEach(key => appleless_obj[key] = fruits[key]);
console.dir(appleless_obj);

Or as a function:

var fruits = {
    "red" : "apple",
    "blue" : "blueberry",
    "yellow" : "banana"
}

function remove_fruit(fruit_to_remove,fruits){
  var new_keys = Object.keys(fruits).filter(this_fruit => fruits[this_fruit] !== fruit_to_remove);
  new_obj = {};
  new_keys.forEach(key => new_obj[key] = fruits[key]);  
  return new_obj;
}

console.dir(remove_fruit("apple",fruits));

Answer 4

Simplified using key deletion,

function stripProperty(o, v) {
    return  (delete o[Object.keys(o).splice(Object.values(o).indexOf(v), 1)])?o:0;
}   

    var fruits = {
        "red" : "apple",
        "blue" : "blueberry",
        "yellow" : "banana"
    }

    function stripProperty(o, v) {
        return  (delete o[Object.keys(o).splice(Object.values(o).indexOf(v), 1)])?o:0;
    }   


    console.log(stripProperty(fruits, 'banana'));

Usage,

var fruits = {
    "red" : "apple",
    "blue" : "blueberry",
    "yellow" : "banana"
}

console.log(stripProperty(fruits, 'apple'))