Thanks @jan_blaha. This was really helpful.

you have row and column (c) in xml file (in worksheets folder. sheet1.xml etc).
if a row added in your template you can change it

{{#xlsxReplace "xl/worksheets/sheet1.xml" "worksheet.sheetData[0].row[8].c[4]"}} //You must know the row number and column number here.
<c t="n" s="29"><f>AVERAGE(J15:J{{#sum dat.length 14}}{{/sum}})</f></c>
{{/xlsxReplace}}

if you dont have added row you can add like that
{{#each dat}}
{{#xlsxAdd "xl/worksheets/sheet1.xml" "worksheet.sheetData[0].row"}}
<row r="{{#sum 1 15}}{{/sum}}">
<c r="A{{#sum 1 15}}{{/sum}}" s="28" t="inlineStr"><is><t>{{time}}</t></is></c>
..... you can add other rows.
</row>
{{/xlsxAdd}}
{{/each}}

You can do any changes by going adress like that "worksheet.sheetData[0].row[8].c[4]". //if row exists.

in below code how can I write variable instead of number 1 in row[1]

{{#xlsxReplace "xl/worksheets/sheet1.xml" "worksheet.sheetData[0].row[1].c[6]"}}
<c t="inlineStr"><is><t>{{value}}</t></is></c>
{{/xlsxReplace}}

Hi
change your .xlsx file to .rar file type. Then open it with with winrar. When you open it you will see xl folder. Open that folder. In this folder ther is a file named styles.xml. You can do changes with styles and you can see the changes in jsreport like this
<c r="A{{#adjustRow 3 14}}{{/adjustRow}}" s="20" t="inlineStr"><is><t>{{time}}</t></is></c>
Here s="20" indicates the style number in styles.xml file. This style will be apply to specified cell in column A.
You can observe the styles by opening the sheet1.xml file

Hi
How can I print values like 12% in excel recipe.
Is there any way like t="n" format