let wsrows = [ { wch: 30 }, { wch: 20 }, { wch: 15 }, { wch: 20 }, { wch: 20 }, { wch: 20 }, { wch: 20 }, { wch: 15 }, { wch: 15 }, { wch: 20 }, { wch: 20 } ]; ws['!cols'] = wsrows; code example

Example: set auto width sheetjs

let objectMaxLength = []; 
    for (let i = 0; i < json.length; i++) {
      let value = <any>Object.values(json[i]);
      for (let j = 0; j < value.length; j++) {
        if (typeof value[j] == "number") {
          objectMaxLength[j] = 10;
        } else {
          objectMaxLength[j] =
            objectMaxLength[j] >= value[j].length
              ? objectMaxLength[j]
              : value[j].length;
        }
      }
    }
    console.log(objectMaxLength);

    var wscols = [
      { width: objectMaxLength[0] },  // first column
      { width: objectMaxLength[1] }, // second column
      { width: objectMaxLength[2] }, //...
      { width: objectMaxLength[3] }, 
      { width: objectMaxLength[4] },
      { width: objectMaxLength[5] }, 
      { width: objectMaxLength[6] }, 
      { width: objectMaxLength[7] }, 
      { width: objectMaxLength[8] },
      { width: objectMaxLength[9] }
    ];

    const worksheet: XLSX.WorkSheet = XLSX.utils.json_to_sheet(json);
    worksheet["!cols"] = wscols;