export async function AppendOnlyArray()

in src/global_append_only_array.js [15:90]

• 25 lines of code
• 3 McCabe index (conditional complexity)

export async function AppendOnlyArray(startValue, arrayName) {
  let arrayWrapper = {}
  let localArray = startValue
  let localChangesQueue = []

  let receivedAllValues = Reactive.boolSignalSource(`${arrayName}_receivedAllValues`)
  receivedAllValues.set(false)

  receivedAllValues.signal.onOn().subscribe(
    event => {
      if (event.newValue) {
        if (localChangesQueue.length > 0) {
          receivedAllValues.set(false)
          arrayWrapper.updateState({
            newValues: localChangesQueue.slice()
          })
          localArray.push(...localChangesQueue)
          localChangesQueue = []
          Time.setTimeout(() => {
            receivedAllValues.set(true)
          }, 50)
        }
      }
  })

  arrayWrapper.setReceivedAllValues = function (newValue) {
    receivedAllValues.set(newValue)
  }

  arrayWrapper.receivedAllValuesSignal = receivedAllValues.signal

  arrayWrapper.compareAndUpdateLocal = function (newArray) {
    const currentLength = localArray.length
    const newLength = newArray.length
    let i
    for (i = 0; i < currentLength && i < newLength; i++) {
      localArray[i] = newArray[i]
    }
    if (newLength > currentLength) {
      for (let j = i; j < newArray.length; j++) {
        localArray.push(newArray[j])
      }
    } else if (newLength < currentLength && newLength != 0) {
      localArray.splice(i, currentLength - newLength)
    }
  }

  // Pushes the new value when the global array is synchronised with at least one peer
  arrayWrapper.push = function (newValue) {
    if (receivedAllValues.signal.pinLastValue()) {
      receivedAllValues.set(false)
      localArray.push(newValue)
      arrayWrapper.updateState({newValues: [newValue]})
      Time.setTimeout(() => {
        receivedAllValues.set(true)
      }, 50)
    } else {
      localChangesQueue.push(newValue)
    }
  }

  // Returns a copy with the current elements of the array
  arrayWrapper.getSnapshot = function (index) {
    return localArray.slice()
  }

  arrayWrapper.length = function () {
    return localArray.length
  }

  arrayWrapper.get = function (index) {
    return localArray[index]
  }

  return arrayWrapper
}