read property 'richText' of undefined

After upgrading to Node.js v6.1.0 (from v5.7.1) the following code which previously worked fine:

   workbook.xlsx.writeFile("my.xlsx");

Causes the following error now:

Unhandled rejection TypeError: Cannot read property 'richText' of undefined
    at utils.inherits.write (C:\Sandboxes\myproj\node_modules\exceljs\lib\xlsx\xform\shared-string-xform.js:56:14)
    at C:\Sandboxes\myproj\node_modules\exceljs\lib\xlsx\xform\shared-strings-xform.js:102:10
    at Array.forEach (native)
    at Function._.each._.forEach (C:\Sandboxes\myproj\node_modules\underscore\underscore.js:78:11)
    at utils.inherits.write (C:\Sandboxes\myproj\node_modules\exceljs\lib\xlsx\xform\shared-strings-xform.js:101:7)
    at BaseXform.toXml (C:\Sandboxes\myproj\node_modules\exceljs\lib\xlsx\xform\base-xform.js:71:10)
    at xml (C:\Sandboxes\myproj\node_modules\exceljs\lib\xlsx\xform\base-xform.js:66:17)
    at C:\Sandboxes\myproj\node_modules\exceljs\lib\xlsx\xlsx.js:698:39
    at Promise._execute (C:\Sandboxes\myproj\node_modules\bluebird\js\release\debuggability.js:272:9)
    at Promise._resolveFromExecutor (C:\Sandboxes\myproj\node_modules\bluebird\js\release\promise.js:473:18)
    at new Promise (C:\Sandboxes\myproj\node_modules\bluebird\js\release\promise.js:77:14)
    at Object.XLSX.addSharedStrings (C:\Sandboxes\myproj\node_modules\exceljs\lib\xlsx\xlsx.js:697:14)
    at C:\Sandboxes\myproj\node_modules\exceljs\lib\xlsx\xlsx.js:942:16
    at tryCatcher (C:\Sandboxes\myproj\node_modules\bluebird\js\release\util.js:16:23)
    at Promise._settlePromiseFromHandler (C:\Sandboxes\myproj\node_modules\bluebird\js\release\promise.js:502:31)
    at Promise._settlePromise (C:\Sandboxes\myproj\node_modules\bluebird\js\release\promise.js:559:18)

[euqen]

This bug is actual for some versions higher than 0.2.4.

[barbalex]

Got it: it happened because we accidentally passed a function instead of a value.