Get array from variable in javascript

Question

I'm looking to get an array from a variable. If it's not already an array I want to return a new array with the variable as the only entry.Example:

toArray('test'); // => ["test"]
toArray(['test']); // => ["test"]

My actual working code is:

var toArray;

toArray = function(o) {
  if (Array.isArray(o)) {
    return o.slice();
  } else {
    return [o];
  }
};

I'd like to know if there is a nicer way for that (native or with underscore.js for example).

In ruby, you can do:

Array('test') # => ["test"]
Array(['test']) # => ["test"]

Your example uses an string, not an object. Your question says "if it's not already [an array]" but returns a new array regardless. What do you really want? — RobG
– RobG, Commented Mar 5, 2013 at 1:20
It could be whatever that it's not an array: object, string, integer, ... — TimPetricola
– TimPetricola, Commented Mar 5, 2013 at 1:24

the system · Accepted Answer · 2013-03-05 01:16:05Z

2

Just use .concat().

[].concat("test");   // ["test"]
[].concat(["test"]); // ["test"]

Arrays will be flattened into the new Array. Anything else will simply be added.

answered Mar 5, 2013 at 1:16

the system

9,35642 silver badges47 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

adeneo · Accepted Answer · 2013-03-05 01:04:54Z

1

function toArray(o) {
  return Array.isArray(o) ? o.slice() : [o];
};

answered Mar 5, 2013 at 1:04

adeneo

319k29 gold badges410 silver badges392 bronze badges

5 Comments

TimPetricola Over a year ago

Yeah it would work but it's actually exactly the same code, just written as a ternary. I'm looking for something else, like a single method. But I actually doubt it exists :)

adeneo Over a year ago

You're not really converting an object to an array, it looks like you're just returning a new array both if it's already an array and if it's a string, so I don't think there is a built in function that does both without some type checking and two different methods, like above.

TimPetricola Over a year ago

Yep you're right, I'm not really converting it. I edited the question to make it more clear. Thanks :)

adeneo Over a year ago

From some of the answers it seems you can just join it with an existing array using concat(), and create an array, regardless of wether or not it's a string or array, so that's neat, even if it does pretty much the same thing.

TimPetricola Over a year ago

Yeah I accepted the concat() way. No need for a new function with it

SeanCannon · Accepted Answer · 2013-03-05 01:05:17Z

0

I believe you can slice it:

var fooObj = {0: 123, 1: 'bar', length: 2};
var fooArr = Array.prototype.slice.call(fooObj);

Demo: http://jsfiddle.net/sh5R9/

answered Mar 5, 2013 at 1:05

SeanCannon

78.1k17 gold badges126 silver badges145 bronze badges

3 Comments

lordvlad Over a year ago

you cannot. in chrome at least not.

Jonathan Lonowski Over a year ago

For numeric keys, sure -- { 0: 123, 1: 'bar', length: 2 }. But, I think the OP is after Array-wrapping more than direct conversion.

TimPetricola Over a year ago

It's not really what I'm looking for. I want to put the object as the first entry of an array (if it's not already one). So the expected result with your object would be: [{0: 123, 1: 'bar', length: 2}]. But it's nice to know that you can call slice on an object!

Collectives™ on Stack Overflow

Get array from variable in javascript

3 Answers 3

Comments

5 Comments

3 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

5 Comments

3 Comments

Your Answer

Sign up or log in

Post as a guest

Related