无法读取属性＆＃39;推送＆＃39;未定义？

Question

我有以下简单的代码：

  export class Years {

      private years: number[];
      private currentYear: number;

      constructor() {
        this.currentYear = new Date().getFullYear();
        this.years.push(this.currentYear + 1);
        for (let i = this.currentYear; i < this.currentYear - 5; i--) {
          this.years.push(i);
        }
      }
}

它给了我一个错误：Cannot read property 'push' of undefined?？为什么我的数据类型正确为数组？

Answer 1

您必须初始化年​​份以清空数组，否则它为空

 private years: number[] = [];