src/circular-buffer.ts

   1 /**
   2  * Default buffer size
   3  */
   4 export const defaultBufferSize = 2048
   5
   6 /**
   7  * Circular buffer
   8  */
   9 export class CircularBuffer<T> {
  10   private readonly readIdx: number
  11   private writeIdx: number
  12   private items: Array<T | undefined>
  13   private readonly maxArrayIdx: number
  14
  15   /**
  16    * @param size - Buffer size
  17    * @returns CircularBuffer
  18    */
  19   constructor (size: number = defaultBufferSize) {
  20     this.checkSize(size)
  21     this.readIdx = 0
  22     this.writeIdx = 0
  23     this.maxArrayIdx = size - 1
  24     this.items = new Array<T | undefined>(size)
  25   }
  26
  27   /**
  28    * Puts data into buffer
  29    *
  30    * @param data - Data to push
  31    */
  32   public put (data: T): void {
  33     this.items[this.writeIdx] = data
  34     this.writeIdx = this.writeIdx === this.maxArrayIdx ? 0 : this.writeIdx + 1
  35   }
  36
  37   /**
  38    * Returns buffer as array
  39    *
  40    * @returns T[]
  41    */
  42   public toArray (): T[] {
  43     return this.items.filter(item => item != null) as T[]
  44   }
  45
  46   private checkSize (size: number): void {
  47     if (!Number.isSafeInteger(size)) {
  48       throw new TypeError(
  49         `Invalid circular buffer size: ${size} is not an integer`
  50       )
  51     }
  52     if (size < 0) {
  53       throw new RangeError(`Invalid circular buffer size: ${size} < 0`)
  54     }
  55   }
  56 }