Given a JavaScript object:
var dataObject = {
object1: {id: 1, name: "Fred"},
object2: {id: 2, name: "Wilma"},
object3: {id: 3, name: "Pebbles"}
};
How do I efficiently extract the inner objects into an array? I do not need to maintain a handle on the object[n] IDs.
var dataArray = [
{id: 1, name: "Fred"},
{id: 2, name: "Wilma"},
{id: 3, name: "Pebbles"}]
var dataArray = Object.keys(dataObject).map(function(k){return dataObject[k]});
for (var o = 0, l = dataObject.length; o < l; o++) {} would be even faster than for ... in. Although, map could be quicker when the function inside the map is very complicated, and is processed using multiple threads and webworkers... but yes, in almost all cases a for loop is much faster.
hasOwnProperty internally.
hasOwnProperty to the accepted answer is efficient than this method where an array is built first and it is traversed O(N) space + O(N) time.var dataArray = [];
for(var o in dataObject) {
dataArray.push(dataObject[o]);
}
dataObject.hasOwnProperty(o).
Object.prototype this will break without using hasOwnProperty().
new Array here instead of []?
an unordered collection of properties there is no order to preserve.ES6 version:
var dataArray = Object.keys(dataObject).map(val => dataObject[val]);
Using underscore:
var dataArray = _.values(dataObject);
With jQuery, you can do it like this -
var dataArray = $.map(dataObject,function(v){
return v;
});
ES2017 using Object.values:
const dataObject = {
object1: {
id: 1,
name: "Fred"
},
object2: {
id: 2,
name: "Wilma"
},
object3: {
id: 3,
name: "Pebbles"
}
};
const valuesOnly = Object.values(dataObject);
console.log(valuesOnly)Assuming your dataObject is defined the way you specified, you do this:
var dataArray = [];
for (var key in dataObject)
dataArray.push(dataObject[key]);
And end up having dataArray populated with inner objects.
Using the accepted answer and knowing that Object.values() is proposed in ECMAScript 2017 Draft you can extend Object with method:
if(Object.values == null) {
Object.values = function(obj) {
var arr, o;
arr = new Array();
for(o in obj) { arr.push(obj[o]); }
return arr;
}
}
[Editing and updating my answer. The other answers seem to overlap with mine pretty much, but, I thought I have another ago and provide an alternative].
I present 3 solutions to this problem, based on:
Objects.keys() solution:
let keys = Object.keys(dataObject); // ["object1", "object2", "object3" ];
let keysToResult = keys.map( e => dataObject[e] ); // [{"id":1,"name":"Fred"},{"id":2,"name":"Wilma"},{"id":3,"name":"Pebbles"}]
Object.values solution:
let values = Object.values(dataObject); // [{"id":1,"name":"Fred"},{"id":2,"name":"Wilma"},{"id":3,"name":"Pebbles"}]
Object.entries solution:
let entries = Object.entries(dataObject); // [["object1",{"id":1,"name":"Fred"}],["object2",{"id":2,"name":Wilma"}],["object3",{"id":3,"name":"Pebbles"}]]
let entriesToResult = entries.map( ([k,v]) => v ); [{"id":1,"name":"Fred"},{"id":2,"name":"Wilma"},{"id":3,"name":"Pebbles"}]
All three solutions have their own features.
Object.keys() returns an array with insufficient result. So, we use Array.prototype.map to top up each value in the array to get close to what we want. In general, we can think of Object.keys() combined with map as a mechanism to customize our result list with what we want.
Object.values() is interesting since it discards the key and just returns the results only. In fact, for this problem, this is perfect since the answer requires no further processing.
Object.entries() returns more than what we want since it returns both keys and values. We need to use map to customize our result. In fact, we need to cut out the excess information.
Object.keys(), Object.values() and Object.entries() are all very useful functions which is why I wanted to show all 3 as a solution to this problem. Depending on your specific use case, you may find one to a better fit to solving your problem.
Maybe a bit verbose, but robust and fast
var result = [];
var keys = Object.keys(myObject);
for (var i = 0, len = keys.length; i < len; i++) {
result.push(myObject[keys[i]]);
}
Object.values() method is now supported. This will give you an array of values of an object.
Object.values(dataObject)
Refer: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_objects/Object/values
In case you use d3. you can do d3.values(dataObject) which will give
This one worked for me
var dataArray = Object.keys(dataObject).map(function(k){return dataObject[k]});
