title: Reading first n lines of sheet using xlsx module
body: <p>I am trying to read first five rows of data from an excel sheet using xlsx module. 
  Initially, I tried by using a sheet_to_json method which converts whole sheet data to an array of arrays.</p>
  
  <pre><code>let sheetData = xlsx.utils.sheet_to_json(workbook.Sheets[sheetsList[i]], {
    header: 1,
    defval: '',
    blankrows: true
  });
  </code></pre>
  
  <p>But the problem (out of memory) incurred when the file size is huge(>10K records present in a sheet).</p>
  
  <p>Secondly, I tried using the following link: <a href="https://github.com/SheetJS/js-xlsx/issues/214#issuecomment-96843418" rel="noreferrer">https://github.com/SheetJS/js-xlsx/issues/214#issuecomment-96843418</a>
  But I am getting the following error:</p>
  
  <pre><code>    f:\xxx\node_modules\xlsx\xlsx.js:2774
  function decode_range(range) { var x =range.split(":").map(decode_cell); return {s:x[0],e:x[x.length-1]}; }
                                              ^
  
  TypeError: Cannot read property 'split' of undefined
  </code></pre>
  
  <p>How can I resolve it? or are they any other method or modules that are available such that I can get data from either csv, xlsx, xls?</p>
  
  <p>Thanks!</p>