Class StringMapObserver

src/mutation-observers/string_map_observer.ts:8–117

}

export class StringMapObserver {
  readonly element: Element
  readonly delegate: StringMapObserverDelegate
  private started: boolean
  private stringMap: Map<string, string>
  private mutationObserver: MutationObserver

  constructor(element: Element, delegate: StringMapObserverDelegate) {
    this.element = element
    this.delegate = delegate
    this.started = false
    this.stringMap = new Map()
    this.mutationObserver = new MutationObserver((mutations) => this.processMutations(mutations))
  }

  start() {
    if (!this.started) {
      this.started = true
      this.mutationObserver.observe(this.element, { attributes: true, attributeOldValue: true })
      this.refresh()
    }
  }

  stop() {
    if (this.started) {
      this.mutationObserver.takeRecords()
      this.mutationObserver.disconnect()
      this.started = false
    }
  }

  refresh() {
    if (this.started) {
      for (const attributeName of this.knownAttributeNames) {
        this.refreshAttribute(attributeName, null)
      }
    }
  }

  // Mutation record processing

  private processMutations(mutations: MutationRecord[]) {
    if (this.started) {
      for (const mutation of mutations) {
        this.processMutation(mutation)
      }
    }
  }

  private processMutation(mutation: MutationRecord) {
    const attributeName = mutation.attributeName
    if (attributeName) {
      this.refreshAttribute(attributeName, mutation.oldValue)
    }
  }

  // State tracking