实现计算器计算功能鸿蒙示例代码

inputDelete(len: number) {
    if (len === 0) {
      return;
    }
    let last = this.expressions[len - 1];
    let lastLen = last.length;
    if (lastLen === 1) {
      this.expressions.pop();
      len = this.expressions.length;
    } else {
      this.expressions[len - 1] = last.slice(0, last.length - 1);
    }
    if (len === 0) {
      this.inputValue = '';
      this.calValue = '';
      return;
    }
    if (!CalculateUtil.isSymbol(this.expressions[len - 1])) {
      this.getResult();
    }
  }
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