MapModel

Defined in: api/node/typescript/models.ts:579 ↗

MapModel provides rows that are generated by a map function based on the rows of another model.

Extends

Model<U>

Type Parameters

T

T

item type of source model that is mapped to U.

U

U

the type of the mapped items.

Example

Here we have an ArrayModel holding rows of a custom interface Name and a MapModel that maps the name rows to single string rows.

interface Name {
    first: string;
    last: string;
}

const model = new ArrayModel<Name>([
    { first: "Hans", last: "Emil" },
    { first: "Max", last: "Mustermann" },
    { first: "Roman", last: "Tisch" },
]);

const mappedModel = new MapModel(model, (data) => data.last + ", " + data.first);

// prints "Emil, Hans"
console.log(mappedModel.rowData(0));

Since a MapModel shares row change notifications with its source model, modifications made to the underlying model (for example through ArrayModel.setRowData) are reflected automatically.

Note that “sharing row change notifications” means a MapModel literally reuses its source model’s underlying notification channel — it does not have an independent one. As a consequence, calling MapModel.reset notifies every view bound to that channel, including views bound directly to the source model and views bound to any other MapModel wrapping the same source model instance, not just views bound to this particular MapModel. Only rely on this sharing behavior when the source model is not otherwise displayed on its own or wrapped by another MapModel.

Constructors

Constructor

new MapModel<T, U>(sourceModel, mapFunction): MapModel<T, U>

Defined in: api/node/typescript/models.ts:592 ↗

Constructs a new MapModel that provides a mapped view on the given sourceModel by applying mapFunction on each of its rows.

Parameters

sourceModel

Model<T>

the wrapped model.

mapFunction

(data) => U

maps the data from T to U.

Returns

MapModel<T, U>

Overrides

Model<U>.constructor

Properties

sourceModel

readonly sourceModel: Model<T>

Defined in: api/node/typescript/models.ts:583 ↗

The source model that this MapModel maps rows from.

Methods

[iterator]()

[iterator](): Iterator<U>

Defined in: api/node/typescript/models.ts:196 ↗

Returns

Iterator<U>

Inherited from

Model.[iterator]

filter()

filter(filterFunction): FilterModel<U>

Defined in: api/node/typescript/models.ts:118 ↗

Returns a new Model that only contains the rows of this model for which filterFunction returns true.

Parameters

filterFunction

(data) => boolean

returns true if a row should be visible.

Returns

FilterModel<U>

a new FilterModel that wraps the current model.

Inherited from

Model.filter

insertRow()

insertRow(_index, _data): void

Defined in: api/node/typescript/models.ts:190 ↗

Implementations of this function must add a row at the specified index, pushing all next rows to the right.

Parameters

_index

number

index of the row to insert.

_data

U

new data item to store in a new row.

Returns

void

Inherited from

Model.insertRow

map()

map<U>(mapFunction): MapModel<U, U>

Defined in: api/node/typescript/models.ts:108 ↗

Returns a new Model where all elements are mapped by the function mapFunction.

Type Parameters

U

U

Parameters

mapFunction

(data) => U

maps the data from T to U.

Returns

MapModel<U, U>

a new MapModel that wraps the current model.

Inherited from

Model.map

pushRow()

pushRow(_data): void

Defined in: api/node/typescript/models.ts:168 ↗

Implementations of this function must add a line to the model with the provided data.

Parameters

_data

U

new data item to store in a new row.

Returns

void

Inherited from

Model.pushRow

removeRow()

removeRow(_index): void

Defined in: api/node/typescript/models.ts:178 ↗

Implementations of this function must remove the row at the specified index.

Parameters

_index

number

index of the row to remove.

Returns

void

Inherited from

Model.removeRow

reset()

reset(): void

Defined in: api/node/typescript/models.ts:629 ↗

Notifies the run-time that the mapped view has changed. Call this if the map function’s result depends on state external to the source model and that state has changed, so that the mapped view reflects the current data.

Since MapModel shares its notification channel with the source model (see the class documentation), this also triggers a full reload of any other view bound to the same source model instance, including views bound to the source model directly or to a sibling MapModel.