get one item from an array of name,value JSON

Question

I have this array:

var arr = []; arr.push({name:"k1", value:"abc"}); arr.push({name:"k2", value:"hi"}); arr.push({name:"k3", value:"oa"}); 

is it possible to do get the value or a specific element by knowing the name ?

something like this:

arr['k2'].value 

or

arr.get('k1') 

Answer 1

I know this question is old, but no one has mentioned a native solution yet. If you're not trying to support archaic browsers (which you shouldn't be at this point), you can use array.filter:

var arr = [];  arr.push({name:"k1", value:"abc"});  arr.push({name:"k2", value:"hi"});  arr.push({name:"k3", value:"oa"});    var found = arr.filter(function(item) { return item.name === 'k1'; });    console.log('found', found[0]);

Check the console.

You can see a list of supported browsers here.

In the future with ES6, you'll be able to use array.find.

Answer 2

Arrays are normally accessed via numeric indexes, so in your example arr[0] == {name:"k1", value:"abc"}. If you know that the name property of each object will be unique you can store them in an object instead of an array, as follows:

var obj = {}; obj["k1"] = "abc"; obj["k2"] = "hi"; obj["k3"] = "oa";  alert(obj["k2"]); // displays "hi" 

If you actually want an array of objects like in your post you can loop through the array and return when you find an element with an object having the property you want:

function findElement(arr, propName, propValue) {   for (var i=0; i < arr.length; i++)     if (arr[i][propName] == propValue)       return arr[i];    // will return undefined if not found; you could return a default instead }  // Using the array from the question var x = findElement(arr, "name", "k2"); // x is {"name":"k2", "value":"hi"} alert(x["value"]); // displays "hi"  var y = findElement(arr, "name", "k9"); // y is undefined alert(y["value"]); // error because y is undefined  alert(findElement(arr, "name", "k2")["value"]); // displays "hi";  alert(findElement(arr, "name", "zzz")["value"]); // gives an error because the function returned undefined which won't have a "value" property