SheetJS/js-xlsx modify table header

We often usejson_to_sheetThe method converts the json data to a worksheet (representing a table in the excel file), and finally exports the excel table. The column header will use the data key name by default, but a convenient Chinese table header is needed to view the data conveniently.

const data = [
    {
        name: 'jzx',
        age: 17
    },
    {
        name: 'wmp',
        age: 17
    }
]

const fields = [ 'name', 'age' ]
const workSheet = XLSX.utils.json_to_sheet(
    data, 
    { 
        header: fields
    }
)

console.log(workSheet)：

You can see that each property name of the object is very regular, allletter+digitalThe combination,letterMeans column,digitalMeans line, line from1Start counting,ColumnFrom lettersAStart untilZ, The letters that are superimposed on the back in order, that means the first27Columns should use lettersAAMeans, and so on.

Attribute valuetRepresentation type,vIs the original value. You can see that the list header will be represented by the first line, which isA1,B1, The header adds two rows of data, a total of three rows.

You can directly replaceA1,B1Corresponding header name, but this is very troublesome when the number of columns is increased to dozens. It is best to use a loop to process such regular data.

First you need to get all the columnsletter, After getting all the columns, add1Is all the header fields, and then replace the attribute valuevAttribute, just use it hereXLSX.utils.encode_colwithXLSX.utils.decode_rangeMethod, andworkSheetof!refAttributes.

First lookworkSheetof!refAttributes:

workSheet['!ref'])
// A1:B3
// The first cell before the colon and the last cell after the colon

XLSX.utils.decode_rangeThe method can convert the corresponding letters into numbers:

const range = XLSX.utils.decode_range(ws['!ref'])
// The value of the range object:
{
    s: {
        c: 0, // first row
        r: 0  // first row
    },
    e: {
        c: 1, // the second list
        r: 2 // The third row
    }
}

sRefers to the first cell,cRefers to the column,rMeans line,eIs the last cell, ok, with this object, we know thisworkSheetAll columns are fromNumber 0ToNumber 1Corresponding to all letters, use lastXLSX.utils.encode_colMethod, just convert the number to the corresponding letter, example:

XLSX.utils.encode_col(0) // A first column
XLSX.utils.encode_col(26) // AA column 26
XLSX.utils.encode_col(27) // AB

Finally encapsulate a complete method to set the header:

// Create a worksheet, set the table header during the creation process
function createWs(data, fields, titles) {
    const ws = XLSX.utils.json_to_sheet(
        data, 
        { 
            header: fields
        }
    )
    const range = XLSX.utils.decode_range(ws['!ref'])
    
    for(let c = range.s.c; c <= range.e.c; c++) {
      const header = XLSX.utils.encode_col(c) + '1'
      ws[header].v = titles[ ws[header].v ]
    }
    
    return ws
}

const titles = {
    name: 'Name',
    age: 'age'
}
const fields = [ 'name', 'age' ]
const data = [
    {
        name: 'jzx',
        age: 17
    },
    {
        name: 'wmp',
        age: 17
    }
]
const ws = createWs(
    data,
    fields,
    titles
)

console.log(ws)

The header has been modified.