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;