hnh-map/frontend-nuxt/lib/UniqueList.ts

/**
 * Elements should have unique field "id"
 */
export interface Identifiable {
  id: number | string
}

export class UniqueList<T extends Identifiable> {
  elements: Record<string, T> = {}

  update(
    dataList: T[],
    addCallback?: (it: T) => void,
    removeCallback?: (it: T) => void,
    updateCallback?: (oldElement: T, newElement: T) => void
  ): void {
    const elementsToAdd = dataList.filter((it) => this.elements[String(it.id)] === undefined)
    const elementsToRemove: T[] = []
    for (const id of Object.keys(this.elements)) {
      if (dataList.find((up) => String(up.id) === id) === undefined) {
        const el = this.elements[id]
        if (el) elementsToRemove.push(el)
      }
    }
    if (removeCallback) {
      elementsToRemove.forEach((it) => removeCallback(it))
    }
    if (updateCallback) {
      dataList.forEach((newElement) => {
        const oldElement = this.elements[String(newElement.id)]
        if (oldElement) {
          updateCallback(oldElement, newElement)
        }
      })
    }
    if (addCallback) {
      elementsToAdd.forEach((it) => addCallback(it))
    }
    elementsToRemove.forEach((it) => delete this.elements[String(it.id)])
    elementsToAdd.forEach((it) => (this.elements[String(it.id)] = it))
  }

  getElements(): T[] {
    return Object.values(this.elements)
  }

  byId(id: number | string): T | undefined {
    return this.elements[String(id)]
  }
}