What is the syntax to find a value in an array of objects by a property?

Question

What is the syntax to find a value in an array object?

var pStData = [];

pStData.push({ st: 'WV', geom: 'xxx' });
pStData.push({ st: 'TX', geom: 'yyy' });

var sGeom = pStData.find(pStData => pStData.st == 'TX').geom;

console.log(sGeom);

In my code, pStData.find(pStData => pStData.st == 'TX') is undefined.

There is zero jQuery in your code. It also works as expected. — Guy Incognito, Sep 16 '20 at 22:09
sorry, i did not say jQuery is in my code. I am asking for a jQuery solution. — Doug Moore, Sep 16 '20 at 22:14
You don't need a jQuery solution if you create the array correctly... You're looking for a sledgehammer to crack a walnut. If you really want a jQuery solution, look up $.each — Steve Childs, Sep 16 '20 at 22:23
@DougMoore The problem you’re describing, any sensible solution, and your code are all completely unrelated to jQuery and _should_ contain no jQuery. You’re working with basic JavaScript here. You’re asking for JavaScript solutions. — Sebastian Simon, Sep 16 '20 at 22:43
[Duplicate](https://www.google.com/search?q=site%3Astackoverflow.com+js+find+value+in+array+of+objects+by+property) of [Find object by id in an array of JavaScript objects](https://stackoverflow.com/q/7364150/4642212). Your code works as-is. There is no issue. — Sebastian Simon, Sep 16 '20 at 22:47
ok it looks like my variable call into the index had an extra space, so when I .trim() it started working in all versions posted. — Doug Moore, Sep 16 '20 at 23:06

score 0 · Accepted Answer · edited Sep 21 '20 at 18:18

Other than no jQuery there at all, you're defining the array as an array of objects. Define an object like this:

var pStData = {};
pStData['WV'] = {geom: 'xxx'};
pStData['TX'] = {geom: 'yyy'};

Then you can access simply by

var sGeom = pStData['WV'].geom;

You can also access it via

var sGeom = pStData.WV.geom;

Of course you don't need to define the object if you're only looking up a string value, for example this would work just as well.

var pStData = {};
pStData['WV'] = 'xxx';
pStData['TX'] = 'yyy';

However, defining it as an object does future proof your code, should you need to add extra data values later. Never be afraid to do a bit of future proofing, it can save a lot of work later.

@DougMoore You’re not using the `{ geom: "`…`" }` objects. — Sebastian Simon, Sep 16 '20 at 22:40

score 0 · Answer 2 · answered Sep 16 '20 at 22:49

Use this function:

 function findObjectInArrayByProperty(array, propertyName, propertyValue) {
      return array.find((o) => { return o[propertyName] === propertyValue });
 }

So, in your case:

function findObjectInArrayByProperty(array, propertyName, propertyValue) {
      return array.find((o) => { return o[propertyName] === propertyValue });
 }
     var pStData = [];
     pStData.push({ st: 'WV', geom: 'xxx' });
     pStData.push({ st: 'TX', geom: 'yyy' });
     var resultObj = findObjectInArrayByProperty(pStData, "st", "TX");
     
     console.log(resultObj);

output -> { st: 'TX', geom: 'yyy' }

What is the syntax to find a value in an array of objects by a property?

2 Answers2