lost-sia/src/utils/hist.js

Single Image Annotation Tool

class UndoRedo {
  constructor(maxElements = 100) {
    this.hist = []
    this.pointer = 0
    this.maxElements = maxElements
  }

  push(entry, description = 'No description') {
    const histEl = {
      entry,
      description,
    }
    if (this.pointer !== 0) {
      while (this.pointer !== 0) {
        this.pointer--
        this.hist.shift()
      }
    }
    this.hist.unshift(histEl)
    if (this.hist.length > this.maxElements) {
      this.hist.pop()
    }
  }

  undo() {
    if (this.pointer + 1 < this.hist.length) {
      // const element =
      this.pointer++
      return this.hist[this.pointer]
    } else {
      return this.hist[this.hist.length - 1]
    }
  }

  undoMia() {
    if (this.pointer + 1 < this.hist.length) {
      this.pointer++
      return this.hist[this.pointer - 1]
    } else {
      return this.hist[this.hist.length - 1]
    }
  }

  redo() {
    if (this.pointer - 1 >= 0) {
      this.pointer--
      return this.hist[this.pointer]
    } else {
      return this.hist[0]
    }
  }

  getHist() {
    return this.hist
  }

  clearHist() {
    this.hist = []
  }

  isEmpty() {
    return this.hist.length === 0
  }
}

export default UndoRedo