build(matrix) {
    this.keys = [];
    this.data = [];
    if (!matrix || matrix.length < 2 || !matrix[0] || matrix[0].length < 1) {
      this.name = '';
      return;
    }
    this.name = matrix[0][0].w;
    let row = matrix[1];
    for (let i = 0, l = row.length; i < l; i += 1) {
      if (row[i] && row[i].w) {
        this.keys.push(row[i].w);
      } else {
        this.keys.push(`_column_${i}`);
      }
    }
    for (let i = 2, li = matrix.length; i < li; i += 1) {
      row = matrix[i];
      const obj = {};
      for (let j = 0, lj = row.length; j < lj; j += 1) {
        obj[this.keys[j]] = row[j] && row[j].w ? row[j].w : undefined;
      }
      this.data.push(obj);
    }
  }
Build the instance from a block of the excel representing the table.
@param {Object[][]} block Block of data directly from the excel.