@reduxjs/toolkit/src/entities/utils.ts

The official, opinionated, batteries-included toolset for efficient Redux development

import { IdSelector } from './models'

export function selectIdValue<T>(entity: T, selectId: IdSelector<T>) {
  const key = selectId(entity)

  if (process.env.NODE_ENV !== 'production' && key === undefined) {
    console.warn(
      'The entity passed to the `selectId` implementation returned undefined.',
      'You should probably provide your own `selectId` implementation.',
      'The entity that was passed:',
      entity,
      'The `selectId` implementation:',
      selectId.toString()
    )
  }

  return key
}