[Home](./index.md) > [rc-js-util](./rc-js-util.md) > [\_Map](./rc-js-util._map.md) ## \_Map class Utilities that apply to `Map`. **Signature:** ```typescript export declare class _Map ``` ## Properties

Property	Modifiers	Type	Description
[addToSet](./rc-js-util._map.addtoset.md)	`static` `readonly`	typeof mapAddToSet	Used with maps that store sets. Where a set exists for a given key the value will be added to that set, otherwise a new set will be created containing the value.
[arrayMap](./rc-js-util._map.arraymap.md)	`static` `readonly`	typeof mapArrayMap	Like `Array.map` but with a `Map` input. Outputs an `Array`.
[clearingDeleteFromSet](./rc-js-util._map.clearingdeletefromset.md)	`static` `readonly`	typeof mapClearingDeleteFromSet	Used with maps that store sets. Where a set exists for a given key the value will be removed from that set, if it is empty after removal, then the set is deleted.
[concat](./rc-js-util._map.concat.md)	`static` `readonly`	typeof mapConcat	Used with maps that store arrays. Where an array exists for a given key the values will be appended to that array, otherwise a copy of values array will be inserted.
[deleteFromSet](./rc-js-util._map.deletefromset.md)	`static` `readonly`	typeof mapDeleteFromSet	Used with maps that store sets. Where a set exists for a given key the value will be removed from that set.
[deleteGet](./rc-js-util._map.deleteget.md)	`static` `readonly`	typeof mapDeleteGet	Get the stored value if present, then delete the key.
[entriesToArray](./rc-js-util._map.entriestoarray.md)	`static` `readonly`	typeof mapEntriesToArray	Converts a `Map` into an `Array` of its key value pairs.
[firstKey](./rc-js-util._map.firstkey.md)	`static` `readonly`	typeof mapFirstKey	Gets the first inserted key in a `Map`.
[firstValue](./rc-js-util._map.firstvalue.md)	`static` `readonly`	typeof mapFirstValue	Gets the first inserted value in a `Map`.
[initializeGet](./rc-js-util._map.initializeget.md)	`static` `readonly`	typeof mapInitializeGet	Gets the value from a `Map` for a given key, where the value is `undefined` or hasn't been set, the callback's return will be inserted into the `Map` and returned.
[intersect](./rc-js-util._map.intersect.md)	`static` `readonly`	typeof mapIntersect	Does not check value equality, only key. Takes items from A. See [mapIntersect()](./rc-js-util.mapintersect.md).
[keysToArray](./rc-js-util._map.keystoarray.md)	`static` `readonly`	typeof mapKeysToArray	Converts a `Map` into an `Array` of its keys.
[push](./rc-js-util._map.push.md)	`static` `readonly`	typeof mapPush	Used with maps that store arrays. Where an array exists for a given key the value will be appended to that array, otherwise a new array will be created containing the value.
[removeManyFromArray](./rc-js-util._map.removemanyfromarray.md)	`static` `readonly`	typeof mapRemoveManyFromArray	Used with maps that store sets. Where a set exists for a given key the value will be added to that set, otherwise a new set will be created containing the value.
[removeOneFromArray](./rc-js-util._map.removeonefromarray.md)	`static` `readonly`	typeof mapRemoveOneFromArray	Used with maps that store arrays. Where an array exists for a given key the value will be removed from that array.
[reportingAddToSet](./rc-js-util._map.reportingaddtoset.md)	`static` `readonly`	typeof mapReportingAddToSet	Used with maps that store sets. Where a set exists for a given key the value will be added to that set, otherwise a new set will be created containing the value.
[setDifference](./rc-js-util._map.setdifference.md)	`static` `readonly`	typeof mapSetDifference	returns items in A not in B.
[symmetricDifference](./rc-js-util._map.symmetricdifference.md)	`static` `readonly`	typeof mapSymmetricDifference	Returns a map with keys in A not in B, and keys in B not in A.
[union](./rc-js-util._map.union.md)	`static` `readonly`	typeof mapUnion	Returns a map with keys from both A and B. If both A and B have the same key the value from B will be used.
[valuesToArray](./rc-js-util._map.valuestoarray.md)	`static` `readonly`	typeof mapValuesToArray	Converts a `Map` into an `Array` of its values.