JS/jQuery: Filter object properties by array

Question

Lets have an example JS object (aka "associative array"):

var zoo = {
  monkey: { legs: 4, color: "black" },
  fish: { legs: 0, color: "yellow" },
  turtle: { legs: 4, color: "green" },
  emu: { legs: 2, color: "gray" },
};

Now I want to retrieve a nested object (aka "subarray") of aquatic animals. Is there a standard JS/jQuery construct or function to filter object properties by array ("index an array by array"), i.e. something like:

var aquatic = zoo["fish", "turtle"];

The result should obviously be { { legs: 0, color: "yellow" }, { legs: 4, color: "green" } }.

Or is a for loop the simplest solution here?

"standard JS/jQuery construct"... jQuery is not a language. — evolutionxbox
– evolutionxbox, Commented Apr 11, 2017 at 9:14
First its a JS Object. Second, you do not have subarrays. You have nested objects. Third, yes you can use for..in to loop over properties of an object — Rajesh Dixit
– Rajesh Dixit, Commented Apr 11, 2017 at 9:15
@evolutionxbox: I never said jQuery would be a language :-) And I know that "associative array" is actually an object. Anyway, for JS non-professionals like me, associative array is a more explicit term, that's why I used it. JS objects behave pretty much like associative arrays. But if my terminology offends you, I can surely edit the text. Just let me know. — yman
– yman, Commented Apr 11, 2017 at 9:44

Nenad Vracar · Accepted Answer · 2017-04-11 09:15:19Z

5

You can use map() and return array of objects.

var zoo = {
  monkey: { legs: 4, color: "black" },
  fish: { legs: 0, color: "yellow" },
  turtle: { legs: 4, color: "green" },
  emu: { legs: 2, color: "gray" },
};
var aquatic = ["fish", "turtle"];

var result = aquatic.map(e => zoo[e]);
console.log(result)

answered Apr 11, 2017 at 9:15

Nenad Vracar

122k16 gold badges160 silver badges184 bronze badges

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

9 Comments

evolutionxbox Over a year ago

Yay! An answer with no for loop!

Cerbrus Over a year ago

@evolutionxbox: No for loop, but make no mistake, .map is still a loop.

evolutionxbox Over a year ago

@Cerbrus sure, but only in a recursive function sense.

Nenad Vracar Over a year ago

You can see what map() is doing in developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/… Polyfill, it is using while loop.

evolutionxbox Over a year ago

@NenadVracar again sure, but it can also be written without a for/do/while loop.

|

Collectives™ on Stack Overflow

JS/jQuery: Filter object properties by array

1 Answer 1

9 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

9 Comments

Your Answer

Sign up or log in

Post as a guest

Related