判断重复组成新的一维组成三维数组

      var dates = [
        "2020-08-01",
        "2020-08-02",
        "2020-08-05",
        "2021-07-01",
        "2021-07-02",
        "2021-08-10",
      ];
      var columns = [];
      dates.forEach((element) => {
        var elements = element.split("-");
        var yearColumn = this.getColumn(columns, elements[0]);
        if (!yearColumn) {
          yearColumn = { text: elements[0], children: [] };
        }

        var monthColumn = this.getColumn(yearColumn.children, elements[1]);
        if (!monthColumn) {
          monthColumn = { text: elements[1], children: [] };
        }

        var dayColumn = this.getColumn(monthColumn.children, elements[2]);
        if (!dayColumn) {
          dayColumn = { text: elements[2] };
        }

        this.addColumn(columns, yearColumn);
        this.addColumn(yearColumn.children, monthColumn);
        this.addColumn(monthColumn.children, dayColumn);
      });
      console.log(columns);
      return columns;
    },
      getColumn(columns, text) {
      for (let column of columns) {
        if (column.text && column.text == text) {
          return column;
        }
      }
    },
    addColumn(columns, newColumn) {
      var notContain = true;
      for (let column of columns) {
        if (column.text && column.text == newColumn.text) {
          notContain = false;
          return;
        }
      }
      if (notContain) {
        columns.push(newColumn);
      }

      return columns;
    },