In case you missed it, JavaScript finally implemented a groupBy static method for Object and Map:

Map.groupBy(iterable, callbackFn)
Object.groupBy(iterable, callbackFn)

Example usage from MDN:

const inventory = [
{ name: "asparagus", type: "vegetables", quantity: 9 },
{ name: "bananas", type: "fruit", quantity: 5 },
{ name: "goat", type: "meat", quantity: 23 },
{ name: "cherries", type: "fruit", quantity: 12 },
{ name: "fish", type: "meat", quantity: 22 },
];

....

const restock = { restock: true };
const sufficient = { restock: false };
const result = Map.groupBy(inventory, ({ quantity }) =>
quantity < 6 ? restock : sufficient,
);
console.log(result.get(restock));
// [{ name: "bananas", type: "fruit", quantity: 5 }]

....

const result = Object.groupBy(inventory, ({ type }) => type);

/* Result is:
{ vegetables: [
{ name: 'asparagus', type: 'vegetables', quantity: 5 },
],
fruit: [
{ name: "bananas", type: "fruit", quantity: 0 },
{ name: "cherries", type: "fruit", quantity: 5 }
],
meat: [
{ name: "goat", type: "meat", quantity: 23 },
{ name: "fish", type: "meat", quantity: 22 }
]
} */

More info:

<https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/groupBy>
<https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map/groupBy>

Browser Availability:

<https://caniuse.com/?search=groupby>

If you're using the Babel compiler, here is the core-js setting:

<https://github.com/zloirock/core-js#array-grouping>

On Monday, 21 August 2023 at 20:42:18 UTC+2, Michael Haufe (TNO) wrote:

> In case you missed it, JavaScript finally implemented
> a groupBy static method for Object and Map

You might have missed that it's neither decently supported,
nor, as for the enthusiasm, it has anything to do with the
aggregation operator by the same name, in fact, with any
aggregation at all: this "groupBy" is more of a "partitionBy"
and can be implemented in one line of code with an array
reduce over the input's keys. Indeed, I'd call it plain clutter.

Julio

On Saturday, September 2, 2023 at 4:50:21 AM UTC-5, Julio Di Egidio wrote:
> On Monday, 21 August 2023 at 20:42:18 UTC+2, Michael Haufe (TNO) wrote:
>
> > In case you missed it, JavaScript finally implemented
> > a groupBy static method for Object and Map
> You might have missed that it's neither decently supported,
> nor, as for the enthusiasm, it has anything to do with the
> aggregation operator by the same name, in fact, with any
> aggregation at all: this "groupBy" is more of a "partitionBy"
> and can be implemented in one line of code with an array
> reduce over the input's keys. Indeed, I'd call it plain clutter.
>
> Julio

[sad trombone warbling descending glissando w/plunger mute]

On Saturday, September 2, 2023 at 4:50:21 AM UTC-5, Julio Di Egidio wrote:
> On Monday, 21 August 2023 at 20:42:18 UTC+2, Michael Haufe (TNO) wrote:
>
> > In case you missed it, JavaScript finally implemented
> > a groupBy static method for Object and Map
> You might have missed that it's neither decently supported,

In case you missed it, I provided availability statistics in my post plus the babel plugin.

> nor, as for the enthusiasm, it has anything to do with the
> aggregation operator by the same name, in fact, with any
> aggregation at all: this "groupBy" is more of a "partitionBy"
> and can be implemented in one line of code with an array
> reduce over the input's keys. Indeed, I'd call it plain clutter.

Given the Universality and Expressiveness of Fold [1], we can say that about most functions/methods

[1] <https://www.cs.nott.ac.uk/~pszgmh/fold.pdf>

On Sunday, 3 September 2023 at 16:56:01 UTC+2, Michael Haufe (TNO) wrote:
> On Saturday, September 2, 2023 at 4:50:21 AM UTC-5, Julio Di Egidio wrote:
> > On Monday, 21 August 2023 at 20:42:18 UTC+2, Michael Haufe (TNO) wrote:
> >
> > > In case you missed it, JavaScript finally implemented
> > > a groupBy static method for Object and Map
> >
> > You might have missed that it's neither decently supported,
>
> In case you missed it, I provided availability statistics in my
> post plus the babel plugin.

You provided statistics that apparently you can't read.

> > nor, as for the enthusiasm, it has anything to do with the
> > aggregation operator by the same name, in fact, with any
> > aggregation at all: this "groupBy" is more of a "partitionBy"
> > and can be implemented in one line of code with an array
> > reduce over the input's keys. Indeed, I'd call it plain clutter.
>
> Given the Universality and Expressiveness of Fold [1], we can
> say that about most functions/methods

No, we can't say what I have said of most functions/methods,
but again, you can't even read, apparently.

EOD.

Julio

Michael Haufe (TNO), 2023-08-21 20:42:

> In case you missed it, JavaScript finally implemented a groupBy static method for Object and Map:
>
> Map.groupBy(iterable, callbackFn)
> Object.groupBy(iterable, callbackFn)

Which is not widely supported yet:

<https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/groupBy#browser_compatibility>

--
Arno Welzel
https://arnowelzel.de

Omg, the little italian was at it again. How cringe...
What is he, a Bolchevik that is about to kill the Romanov Family?

Julio Di Egidio schrieb:
> On Monday, 21 August 2023 at 20:42:18 UTC+2, Michael Haufe (TNO) wrote:
>
>> In case you missed it, JavaScript finally implemented
>> a groupBy static method for Object and Map
>
> You might have missed that it's neither decently supported,
> nor, as for the enthusiasm, it has anything to do with the
> aggregation operator by the same name, in fact, with any
> aggregation at all: this "groupBy" is more of a "partitionBy"
> and can be implemented in one line of code with an array
> reduce over the input's keys. Indeed, I'd call it plain clutter.
>
> Julio
>

On Sunday, September 3, 2023 at 10:39:28 AM UTC-5, Arno Welzel wrote:
> Michael Haufe (TNO), 2023-08-21 20:42:
> > In case you missed it, JavaScript finally implemented a groupBy static method for Object and Map:
> >
> > Map.groupBy(iterable, callbackFn)
> > Object.groupBy(iterable, callbackFn)
> Which is not widely supported yet:
>
> <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/groupBy#browser_compatibility>
>

Which I shared already in my OP:

<https://caniuse.com/?search=groupby>

Hence my reference to the polyfill:

<https://github.com/zloirock/core-js#array-grouping>