sheet_to_json doesn't output anything for a blank cell

It seems like using sheet_to_json doesn’t handle blank cells very well. I want to keep them in my script (I’m parsing an xlsx file and outputting a csv), but a blank cell outputs an array like:

[ 'foo',
  'bar',
  ,      // the blank value
  'another value' ]

It’d be nice if you got a blank string, since this library seems to recognize the blank value. Would this be possible?

[yang5664]

you don’t need to change anythings, just in function pass opt defval:‘’ that’s it.

XLSX.utils.sheet_to_json(workbook.Sheets[sheet],{defval:""})

[SheetJSDev]

The code as it stands now won’t generate an empty string. The simplest way is to just add a post-processing loop to your code:

for(var i = 0; i != json.length; ++i) for(var j = 0; j != json[i].length; ++j) if(typeof json[i][j] === 'undefined') json[i][j] = "";

As for what it “should” be, why not the number 0? an empty string would be weird in a case like:

[
  [1, 2, 3],
  [4, 5, 6],
  [7, ? ,9]
]

I’d be amenable to adding an option (maybe something called “default” in the options object?), and the changes are relatively simple: https://github.com/SheetJS/js-xlsx/blob/master/xlsx.js#L5293

            val = sheet[cols[C] + rr];
            if(val === undefined || val.t === undefined) continue;

In the bottom half of sheet_to_json, we walk in row-major order across the worksheet. The first line attempts to find if the sheet has a cell at the prescribed address. If the cell doesn’t exist or if its type is not set, then we skip the cell. Instead of just continuing, that second line should set the cell to the empty string:

            if(val === undefined || val.t === undefined) { row[hdr[C]] = ""; continue; }