src/js/algorithm/algorithm-result.js

/**
 * Stores the results generated by running an Algorithm. An instance will be stored in each Algorithm object.
 * @class AlgorithmResult
 */
class AlgorithmResult {

  /**
   * Array of Step objects.
   * @type {Array.<Step>}
   */
  timeline;

  /**
   * Current index in the timeline.
   * @type {number}
   */
  stepIndex;

  /**
   * Constructs an instance of AlgorithmResult.
   * @param  {Array.<string>} nodeFields - Array of fields to store changes for in Node objects.
   * @param  {Array.<string>} edgeFields - Array of fields to store changes for in Edge objects.
   * @constructs AlgorithmResult
   */
  constructor() {
    this.timeline = [];
    this.stepIndex = -1;
  }

  /**
   * Move to the next step in the timeline. Does nothing if already at the end.
   */
  stepForward() {
    if (this.stepIndex === this.timeline.length) {
      return;
    }
    if (this.stepIndex > -1) {
      let finishingStep = this.timeline[this.stepIndex];
      finishingStep.applyPost();
    }
    if (this.stepIndex < this.timeline.length - 1) {
      let nextStep = this.timeline[this.stepIndex + 1];
      nextStep.applyDuring();
      this.stepIndex++;
      return;
    }
    this.stepIndex++;
  }

  /**
   * Move to the previous step in the timeline. Does nothing if already at the beginning.
   */
  stepBackward() {
    if (this.stepIndex === -1) {
      return;
    }
    if (this.stepIndex < this.timeline.length) {
      let redactingStep = this.timeline[this.stepIndex];
      redactingStep.applyPre();
    }
    if (this.stepIndex > 0) {
      let previousStep = this.timeline[this.stepIndex - 1];
      previousStep.applyDuring();
      this.stepIndex--;
      return;
    }
    this.stepIndex--;
  }

  /**
   * Add a Step to the AlgorithmResult.
   * @param {Step} step - The step to add.
   */
  addStep(step) {
    this.timeline.push(step);
  }
}

export { AlgorithmResult };
export default AlgorithmResult;