this post was submitted on 14 Jul 2023
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submitted 1 year ago* (last edited 1 year ago) by KaKi87 to c/[email protected]
 

Hi !

Given the following sample items :

| ID | First name | Age | | ---------- | ---------- |


| | xvZwiCpi | Naomi | 42 | | Nzd9UsGT | Naomi | 24 | | QiDXP2wA | Thea | 53 | | JpYeAY7H | Jeremy | 35 |

I can store these in an array :

const data = [
  { id: 'xvZwiCpi', firstName: 'Frederic', age: 42 },
  { id: 'Nzd9UsGT', firstName: 'Naomi', age: 24 },
  { id: 'QiDXP2wA', firstName: 'Thea', age: 53 },
  { id: 'JpYeAY7H', firstName: 'Mathew', age: 35 }
];

Thus access them the same way by ID :

console.log(data.find(item => item.id === 'xvZwiCpi'));

And by properties :

console.log(data.find(item => item.firstName === 'Frederic').id);

Or I can store these in an object :

const data = {
  'xvZwiCpi': { firstName: 'Frederic', age: 42 },
  'Nzd9UsGT': { firstName: 'Naomi', age: 24 },
  'QiDXP2wA': { firstName: 'Thea', age: 53 },
  'JpYeAY7H': { firstName: 'Mathew', age: 35 }
};

Thus more easily access properties by ID :

console.log(data['xvZwiCpi'].firstName);

But more hardly access ID by properties :

console.log(Object.entries(data).find(([id, item]) => item.firstName = 'Frederic')[0]);

I could duplicate IDs :

const data = {
  'xvZwiCpi': { id: 'xvZwiCpi', firstName: 'Frederic', age: 42 },
  'Nzd9UsGT': { id: 'Nzd9UsGT', firstName: 'Naomi', age: 24 },
  'QiDXP2wA': { id: 'QiDXP2wA', firstName: 'Thea', age: 53 },
  'JpYeAY7H': { id: 'JpYeAY7H', firstName: 'Mathew', age: 35 }
};

To slightly simplify that previous line :

console.log(Object.values(data).find(item => item.firstName = 'Frederic').id);

But what if a single variable type could allow doing both operations easily ?

console.log(data['xvZwiCpi'].firstName);
console.log(data.find(item => item.firstName === 'Frederic').id);

Does that exist ?

If not, I'm thinking about implementing it that way :

const data = new Proxy([
  { id: 'xvZwiCpi', firstName: 'Frederic', age: 42 },
  { id: 'Nzd9UsGT', firstName: 'Naomi', age: 24 },
  { id: 'QiDXP2wA', firstName: 'Thea', age: 53 },
  { id: 'JpYeAY7H', firstName: 'Mathew', age: 35 }
], {
    get: (array, property) =>
        array[property]
        ||
        array.find(item => item.id === property)
});

In which case I'd put it in a lib, but how would this be named ?

I'd also make a second implementation that would enforce ID uniqueness and use Map to map IDs with indexes instead of running find : while the first implementation would be fine for static data, the second one would be more suitable for dynamic data.

Would this make sense ?

Thanks

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[โ€“] [email protected] 0 points 1 year ago (1 children)

I think I misunderstood your initial post (and definitely didn't read it as carefully as I should have ๐Ÿ˜…).

Do I understand your correctly that your goal is a companion object for your arrays that simplifies access? Not a new data structure that you'd user instead of arrays? If so, most of my points are moot.

If your IDs are integers then there is no need for an hybrid at all, precisely because all you have to do is put each item at the same position as their ID.

If you don't treat IDs as opaque values, this is true.

I'll definitely run benchmarks so that users would be aware of performance losses, if any. But use cases of hybrid arrays are mostly small datasets so it usually shouldn't be a concern indeed.

I think my point is actually wrong (it was really late when I was writing my initial response). Performance would be O(n), since that's the worst case scenario.

Anyways, I hope you could take something useful from my answer.

Happy hacking :D

[โ€“] KaKi87 2 points 1 year ago

You may have initially misunderstood my idea, but you did help.

And I implemented it in the meantime, as a library named hybrid-array (after your suggestion).

Not all transformative array methods have been checked yet, no unit testing nor comments have been written yet, no benchmarks have been performed yet, but these will happen.

Thanks.