jwidget/MapUtils

<K, T, U>(map: Iterable<readonly [K, T]>, callback: (value: T, key: K) => U): Map<K, U>

map

Map.

callback

Mapping function.

returns

Mapped map.

Builds a new map of results of callback function call for each map entry with the same keys.

<K, V>(map: Iterable<readonly [K, V]>, callback: (value: V, key: K) => boolean): Map<K, V>

map

Map.

callback

Criteria callback.

returns

Filtered map.

Builds a new map of map entries the callback function returns a truthy value for.

<K, V>(map: Iterable<readonly [K, V]>): Iterable<K>

map

Map.

returns

Map keys.

Returns an Iterable of all map keys. As opposed to native Map.keys, returns an Iterable instead of IterableIterator, so it is stateless and can be reused multiple times to iterate over the map keys.

function pushAndLog<T>(array: T[], values: Iterable<T>) {
    array.push(...values);
    for (const value of values) {
        console.log(value);
    }
}

const array: T[] = [];
const map = new Map([["a", 1], ["b", 2]]);
pushAndLog(array, map.keys()); // wrong: the values will be pushed, but not logged
pushAndLog(array, getIterableKeys(map)); // correct

<K, V>(map: Iterable<readonly [K, V]>): Iterable<V>

map

Map.

returns

Map values.

Returns an Iterable of all map values. As opposed to native Map.values, returns an Iterable instead of IterableIterator, so it is stateless and can be reused multiple times to iterate over the map values.

function pushAndLog<T>(array: T[], values: Iterable<T>) {
    array.push(...values);
    for (const value of values) {
        console.log(value);
    }
}

const array: T[] = [];
const map = new Map([["a", 1], ["b", 2]]);
pushAndLog(array, map.values()); // wrong: the values will be pushed, but not logged
pushAndLog(array, getIterableValues(map)); // correct