核弹发射代码

    const slog = require('single-line-log').stdout;
    
    class ProgressBar {
      constructor(description, barLength) {
    this.description = description || 'Progress';
    this.barLength = barLength || 25;
      }
      render (options) {
    const percent = (options.completed / options.total).toFixed(4);
    const cell_num = Math.floor(percent * this.barLength);
    
    let cell = '';
    for (let i = 0; i < cell_num; i++) {
      cell += '█';
    }
    
    let empty = '';