how to determine if an object is in an array only with a property in javascript?

Question

I have an array of object, and every object has a property named 'done', and other properties. what i want to do is determine whether an object is in that array only by comparing properties except 'done' property.

it works this:

var my_array = [ 
                {'done': false, 'name': 'do homework'}, 
                {'done': true, 'name': 'buy some food'}
               ];
var my_object = {'done': true, 'name': 'do homework'};
if(someFunction(my_arry, my_object)){
  window.alret('called');
}

and I want it display 'called'.

is there some way I can do that? Please help me.

Eric · Accepted Answer · 2013-05-05 14:32:55Z

3

Here's a way to find an object in your array with a matching name:

if(my_array.some(function(x) { return x.name == my_object.name; })) {
    alert("called")
}

If you want to compare all properties:

if(my_array.some(function(x) {
    return Object.keys(x).every(function(k) {
        return k == 'done' || x[k] == my_object[k];
    });
})) {
    alert("called")
}

Although that's sort of pushing our luck with the length of the expression in the if statement, and would be easier to read with things pulled out into functions

edited May 5, 2013 at 14:32

answered May 5, 2013 at 12:04

Eric

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2 Comments

Xotic750 Over a year ago

I assume that by ".all" you mean ".forEach"

Eric Over a year ago

@Xotic750: Nope, I meant .every

3y3 · Accepted Answer · 2013-05-05 12:39:32Z

0

This is simple example with Array.filter:

var my_array = ...;
var my_object = ...;

var done = my_array.filter(function(e){
  for(var opt in my_object) {
    if(opt != 'done') if(!e[opt]||!e[opt]!=my_object[opt]) return false;
  }
  return true;
})
if(done.length){...}

edited May 5, 2013 at 12:39

answered May 5, 2013 at 12:25

3y3

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2 Comments

Bergi Over a year ago

Why filter? There's a better iterator function for this task.

3y3 Over a year ago

@Bergi, This function is suitable when the code will be more difficult - search multiple objects, etc.

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