Multiple ids entity projector

[juanpmarin]

Hi, thanks for this lib ! There is a way to select entites by a list of ids ?

[michaelkrone]

Hello @juanpmarin Out of the box, ngrx-normalizr does not provide a selector for denormalizing a set of id's (Would you like to add this feature by a Pull Request?)

However, it should be possible to achieve selecting a set of id's with the exported selectors. Let's assume you have a state property which holds your selected id's:

const entityState = {
    ...
    selectedIds: string[]
}

Then we need a selector for the state property:

const getSelectedIds = createSelector(
  someStateSelector,
  (state: State) => state.selectedIds
);

We might then create a selector for denormalizing entities for the selected id's with a schema selector:

const schemaSelectors = createSchemaSelectors<Entity>(entitySchema);
const getSelectedEntities = createSelector(
    // get all denormalized entities of the schema
    schemaSelectors.getEntities,
    // get the selected id's from the feature state
    getSelectedIds,
    (entities, ids) => entities.filter(e => ids.indexOf(e.id) > -1)
);

Or maybe as a selector creator function:

function getSelectedEntitiesSelector(ids: string[]) {
    return createSelector(
        schemaSelectors.getEntities,
        entities => entities.filter(e => ids.indexOf(e.id) > -1)
    );
}

The selection could be more efficient if ngrx-normalizr would accept an array of id's for the entitiesProjector, because with the approach above, all entities of the schema bound selector will be denormalized. Good point for a feature!

[juanpmarin]

Hi ! thanks for answering I made a PR, let me know if it fit your expects.

[michaelkrone]

Thank you for your PR @juanpmarin This issue will be closed when 2.1.0 is published.

[juanpmarin]

Hi @michaelkrone Is it possible to release this feature ? I'm gonna need this on my project and I don't want to use the workaround and do the refactor later Thanks !

[michaelkrone]

2.1.0 is published, thank you @juanpmarin

[juanpmarin]

@michaelkrone Great, thanks !