Function map

Reactively maps/filters items from a proxied source array or object to a new proxied array or object.

It iterates over the target proxy. For each item, it calls func.

If func returns a value, it's added to the result proxy under the same key/index.
If func returns undefined, the item is skipped (filtered out).

The returned proxy automatically updates when:

Items are added/removed/updated in the target proxy.
Any proxied data read within the func call changes (for a specific item).

Param: func

A function (value, key) => mappedValue | undefined that transforms each item. It receives the item's value and its key/index. Return undefined to filter the item out.

Returns

A new proxied array or object containing the mapped values.

Template: IN

The type of items in the source proxy.

Template: OUT

The type of items in the resulting proxy.

Example: Map array values

const numbers = proxy([1, 2, 3]);
const doubled = map(numbers, (n) => n * 2);
// doubled is proxy([2, 4, 6])

$(() => console.log(doubled)); // Logs updates
numbers.push(4); // doubled becomes proxy([2, 4, 6, 8])

Example: Filter and map object properties

const users = proxy({
  'u1': { name: 'Alice', active: true },
  'u2': { name: 'Bob', active: false },
  'u3': { name: 'Charlie', active: true }
});

const activeUserNames = map(users, (user) => user.active ? user.name : undefined);
// activeUserNames is proxy({ u1: 'Alice', u3: 'Charlie' })
$(() => console.log(Object.values(activeUserNames)));

users.u2.active = true;
// activeUserNames becomes proxy({ u1: 'Alice', u2: 'Bob', u3: 'Charlie' })

map<K, IN, OUT>(
source: Map<K, IN>,
func: (value: IN, key: K) => undefined | OUT,
): Map<K, OUT>
When using a Map as source.
Type Parameters
- K
- IN
- OUT
Parameters
- source: Map<K, IN>
- func: (value: IN, key: K) => undefined | OUT
Returns Map<K, OUT>
- Defined in aberdeen.ts:2488
map<IN, OUT>(
source: IN[],
func: (value: IN, index: number) => undefined | OUT,
): OUT[]
When using an array as source.
Type Parameters
- IN
- OUT
Parameters
- source: IN[]
- func: (value: IN, index: number) => undefined | OUT
Returns OUT[]
- Defined in aberdeen.ts:2493
map<IN, const IN_KEY extends string | number | symbol, OUT>(
source: Record<IN_KEY, IN>,
func: (value: IN, index: KeyToString<IN_KEY>) => undefined | OUT,
): Record<string | symbol, OUT>
When using an object as source.
Type Parameters
- IN
- const IN_KEY extends string | number | symbol
- OUT
Parameters
- source: Record<IN_KEY, IN>
- func: (value: IN, index: KeyToString<IN_KEY>) => undefined | OUT
Returns Record<string | symbol, OUT>
- Defined in aberdeen.ts:2498

Function map

Param: func

Returns

Template: IN

Template: OUT

Example: Map array values

Example: Filter and map object properties

Type Parameters

Parameters

Returns Map<K, OUT>

Type Parameters

Parameters

Returns OUT[]

Type Parameters

Parameters

Returns Record<string | symbol, OUT>

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