Formula Explorer Pro Beta 4.2

After another 6 months on my quest to create the worlds best tool for exploring, validating, debugging and editing Excel formulas I have made Explorer Pro Beta 4.2 build 418.796 available. Hopefully this will be the final Beta!

The improvements are too numerous to cover in detail but come under these headings:

Improved Functionality Includes:

  • Full support for Dynamic Ranges, Linked Data Types and Rich Data Type Field expressions.
  • Integration with Name Manager Pro to explore and debug Named Formulas.
  • Explore Data Validation formulas, Conditional Format Formulas as well as cell formulas.
  • Support for formulas in 91 languages (thanks to Mourad Louha).
  • Resolved many Mac Excel issues.
  • Lots of bug fixes!

User Interface Cleanup

The previous user interface tried to present too much information
So I simplified, de-cluttered and made it more intuitive.


See my previous post on Explorer Pro for a comparison


Profiling the code showed several areasĀ  that could be significantly improved. Some expensive operations such as coloring large precedent ranges are now optional.

Try it out yourself!

Watch the video Explorer 4.2 Overview

Download the Beta zip file

This build expires on the 31st of March 2019

Posted in Calculation, Debug formulas | Tagged , , , | 4 Comments

Develop Excel Conference

ReactorLogoThe Develop Excel conference will take place in London on Thursday October the 18th 2018. It will be held at the Microsoft Reactor (70 Wilson Street London EC2A 2DB).

Are you responsible for building Excel based Addins and Solutions?

Develop Excel gives you a unique opportunity to meet and learn from the leading international developers of the major Excel extension technologies.

You will:

  • Gain understanding of the comparative merits of available tools, languages and APIs for building Excel extensions
  • Discover the implications for developers and solution builders of Microsoft extensions to core Excel (Co-Authoring, Linked rich data types, built-in Power Query, M Language, Javascript interpreter and APIs, cross-platform common code-base etc.)
  • Meet the Developers responsible for:
    • Microsoft Excel Extensibility including Javascript
    • Excel DNA: .Net and Excel
    • PyXLL: Python and Excel
    • Planatech XLL Plus: C++ and Excel
  • Network with, socialize and meet other Excel developers of Addins and Solutions.

The conference focuses on the two dimensions of Excel Development: the extensions Microsoft are making to the Excel platform and APIs, and the Addins and Solutions that developers can build on this extended base.

This event is a community driven one. There is no profit motive, just a desire to gather the best brains in the Excel extension space together to share knowledge.

Register Now.

Please help us to spread the word and encourage people to join us at Develop Excel.

Free sponsorship offer – see Sponsors page for details.

Special thanks to Microsoft for hosting us at the new London Reactor, and for sending a speaker from the Development team responsible for Excel extensibility.Dev-Team


Posted in .NET, arrays, Excel, JS-API, UDF, VBA, XLL | 2 Comments

Formula Explorer Pro

I have spent most of the last 18 months or so working on a new tool to improve on Excel’s ancient Trace Precedents and Evaluate formulas tools. It is called Formula Explorer Pro, and it is part of FastExcel Manager Pro.

Formula Explorer Pro supports Windows Excel 2007 through Excel 2016 and Office 365, and also Mac Excel 2016.

And now it’s time for a serious test of Beta version 2.5.

(Beta 2.6 Build 362.792 just uploaded)
For a quick overview of Formula Explorer Pro see

And to download the latest Beta version see

Please let me have your feedback, bug reports, suggestions etc.

Explorer Pro Technology

The Explorer Pro Userform is probably the most complex VBA userform I have ever built.


Because it has to work on both Mac and Windows Excel I cannot use any Windows API calls.

The userform:

  • Is modeless
  • Resizeable
  • Has 3 splitter bars
  • Has 2 synchronised Treeview controls and 2 textboxes
  • Adaptive positioning of controls, dependent on both mode and expression selection.

I wish I could say I developed all the technology that underlies this, but it relies heavily on Jan Karel Pieterse and Peter Thornton’s VBA Treeview, and Andy Pope’s work on resizeable userforms and splitter bars …

Other major components of Formula Manager Pro are the formula parser, expression builder, formula indenter, expression evaluator and forward/backward formula debugger.

The formula parser splits a formula into token strings in the local language being used, and then translates the token strings into US English (thanks to Mourad Louha for his help with testing and extending this to 91 different languages).

The expression builder assembles the token strings into expressions that can be evaluated (this includes the strange criteria expressions that occur in functions like SUMIFS).

The formula indenter takes the expressions and builds indented formula strings using the indenting rules that the user has chosen.

The expression evaluator evaluates each of the expressions to produce a scalar or array result. Special handling is needed for things like the criteria expressions in SUMIFS and finding the source precedents that functions like MAX, LOOKUP, SUMIFS, SUMPRODUCT etc are pulling from. Designing the evaluator is hard because there are many different ways you can build sub-expressions from a formula like =A1+B2+C3+D4*E5+F6.

Another tricky evaluation problem is correctly handling implicit intersection, particularly for formulas like =VLOOKUP(A:A,B:F,G:G,H:H) because some of the arguments do implicit intersection and others (B:F) do not. This requires a lookup table for every argument of every native Excel function.

The step-by-step formula debugger actually drove some of the design choices in the expression builder because it requires an unambiguous set of expressions to can be condensed to results for replacing the expression string in the indented formula.

Anyway this is why we need an extended Beta test period!

Posted in Uncategorized | 6 Comments

Excel 2016 Performance Improvements

Excel 2016 Performance Improvements

The Excel team has made a number of performance improvements to Excel 2016. These improvements were rolled out as part of the Office update cycle. The timescale that updates become available to you depends on which update option you are using:

  • Insider
  • Monthly Channel
  • Semi-annual Channel

For more details on the Office 2016 release cadence names see Slow – Fast Level Names.

This post discusses some of the features that have been introduced in Excel 2016 that you can use to improve performance with large or complex workbooks.

Large Address Aware (LAA) Memory improvement for 32-bit Excel

Although 64-bit Excel has extremely large virtual memory limits, 32-bit Excel has been limited to 2 Gigabytes (GB). And many Excel customers have found it difficult to migrate to 64-bit Excel because they use third-party addins and controls that are not available in 64-bit versions.
LAA has now been enabled for 32-bit versions of Excel 2013 and Excel 2016, and will minimize out of memory error messages.
LAA doubles available virtual memory from 2GB to 4GB when using 64-bit Windows, and increases available virtual memory from 2GB to 3GB under 32-bit Windows.

For more details see LAA Capability Change for Excel
To download a tool that shows how much virtual memory is available and how much is being used see Excel Memory Checking Tool

Full Column References

Previously, workbooks using large numbers of full column references and multiple worksheets, for example =COUNTIF(Sheet2!A:A,Sheet3!A1), might use large amounts of CPU and memory when opened, or rows were deleted.
An improvement in Excel 2016 build 16.0.8212.1000 substantially reduces the memory and CPU used in these circumstances.

My test on a workbook with 6 million formulas using full column references failed with an Out of Memory message at 4 GB of virtual memory with Excel 2013 LAA and with Excel 2010 but only used 2 GB virtual memory with Excel 2016.

Structured References

In some circumstances editing Excel Tables where formulas in the workbook use Structured References to the Table could be slow with Excel 2013 and previous versions. This led to the perception that Tables should not be used with large numbers of rows.
Excel 2016 has now fixed this problem.

My test showed an editing operation that took 1.9 seconds in Excel 2013 and Excel 2010 took about 2 milliseconds in Excel 2016.

For more details see Why Structured References are Slow in Excel 2013 but fast in Excel 2016.

Filtering, Sorting Copy/Pasting

The Excel 2016 team studied a number of large workbooks that show slow response when using Filtering, Sorting and Copy/Pasting, and a number of improvements have been made:

In Excel 2013 after Filtering or Sorting or Copy/Pasting many rows Excel could be slow responding or would hang. Performance was highly dependent on the count of all rows between the top visible row and the bottom visible row. An improvement made to the internal calculation of vertical user interface positions in build 16.0.8431.2058 has made these operations much faster.

Opening a workbook with many filtered or hidden rows, merged cells or outlines could cause high CPU load.
A fix in this area was introduced in build 16.0.8229.1000

In the past you could see very slow response after pasting a copied column of cells from a Table with filtered rows where the filter resulted in a large number of separate blocks of rows.
This area has been substantially improved in build 16.0.8327.1000

My test on copy pasting 22000 rows filtered from 44000 rows showed a dramatic improvement:

  • For a Table the time went from 39 seconds in Excel 2013 and 18 seconds in Excel 2010 to 2 seconds in Excel 2016
  • For a Range the time went from 30 seconds in Excel 2013 and 13 seconds in Excel 2010 to virtually instantaneous in Excel 2016

Copying Conditional Formats

In Excel 2013 copy/pasting cells containing conditional formats could be slow.
This has been significantly improved in Excel 2016 build 16.0.8229.0

My test on copying 44000 cells with a total of 386000 conditional format rules showed a substantial improvement:

  • Excel 2010: 70 seconds
  • Excel 2013: 68 seconds
  • Excel 2016: 7 seconds

Adding and deleting Worksheets

My test on Excel 2016 build 16.0.8431.2058 shows a 15-20% speed improvement compared to Excel 2013 when adding and deleting large numbers of worksheets. However Excel 2016 was 5-10% slower than Excel 2010 on this test.

New Functions

Excel 2016 build 16.0.7920.1000 introduced several very useful new worksheet functions:

MAXIFS and MINIFS extend the COUNTIFS/SUMIFS family of functions. These functions have good performance characteristics and should be used to replace equivalent array formulas.

TEXTJOIN and CONCAT let you easily combine text strings from ranges of cells. These functions can replace the slow VBA UDFs typically used in previous versions.

Other Updates to Excel 2016 for Windows

You can find more details of all the other month-by-month improvements that have been made to Excel 2016 at
What’s new in Excel 2016 for Windows.


Posted in Uncategorized | 6 Comments

Strategies for getting the last row in Excel with VBA

Using VBA to get the last row in Excel can be a surprisingly complex task. This post will explore some of the different strategies you can use.

The first thing to do is to decide what you mean by “The Last Row” – some possibilities are:

  • The row Excel considers to be the last row (last row in the Used Range)
  • The last row on a sheet that actually contains data
  • The last row in a range that actually contains data
  • The last data row in a Table ignoring the Totals row
  • The last visible row containing data

Test Data

The test data is constructed to test different last row VBA strategies for ranges and tables.

  • There is a Table in cells $A$4:$A$25. The Table (called Table1) has a header row and a total row.
  • There is a Named Range (called NamedRange) in cells $E$4:$E$30 but $E$26:$E$30 are empty.
  • Rows 5:8, 13:15, 21:25 and 40:42 are hidden so that the Table and Name Range contain more than one visible region.
  • There is data in row 32 below the Table and the Named Range.
  • There is formatting in the hidden row 42.

VBA Strategies

I will look at some of the available strategies for finding the last row.

Used Range

Because Excel internally uses a sparse matrix scheme for the cells in each worksheet (instead of holding a gigantic 16384 by 1048576 array) it has to store information for each cell that has been used. So formatted cells are considered used, as well as cells containing values and formulas. Cells remain flagged as used even when all formatting, values and formulas are removed.

Two VBA methods for working with the used range are Worksheet.UsedRange and the xlCellTypeLastCell option of SpecialCells.

' last row in used range
jLastUsed = oSht.UsedRange.Rows(oSht.UsedRange.Rows.Count).Row
' last visible row in used range
jLastVisibleUsed = oSht.Cells.SpecialCells(xlCellTypeLastCell).Row

For my test data jLastUsed returns 42 because there is some formatting on that row, and xlCellTypeLastCell returns 39, which is the last visible row before row 42.

Range.End(xlDown) and Range.End(xlUp)

These VBA methods mimic pressing Ctrl and the up and down arrows.

For name ranges they skip hidden rows but stop at the row before an empty cell.:

' last visible cell in Named Range using End(xlUp)
jLastVisibleRange = oSht.Range("NamedRange").Offset(oSht.Range("NamedRange").Rows.Count, 0).End(xlUp).Row
' last visible cell in Named Range using End(xlDown)
jLastVisibleRange2 = oSht.Range("NamedRange").End(xlDown).Row

When using End(xlUp) you want start outside the range in an empty cell, so I used Offset to get to the first row below the range. jLastVisibleRange returns 20.

Using End(xlDown) is simpler for a Range: the code start at the first row in the range and ends at the first of the last visible row in the range that contains data and the last row before an empty cell. It also returns 20.

But for Tables End(xlUp) does NOT skip hidden rows!

' last row in Table using End(xlUP) - Note End(xlUp ) behaves differently for tables - includes hidden rows
jLastInTable2 = oSht.Range("Table1").Offset(oSht.Range("Table1").Rows.Count + 1, 0).End(xlUp).Row
' last visible table row using End(xlDown)
jLastVisibleTable = oSht.Range("Table1").End(xlDown).Row

So using End(xlUp) starting from the first row after the end of the table returns Row 25 even though that row is hidden.
But End(xlDown) works the same way with a table as with a Range, and so returns row row 20 which is indeed the last visible row in the table.


My favourite method is to use Range.Find.
Using Find on Formulas includes hidden rows, whereas using Find on Values excludes hidden rows.

You can use this method on Worksheet.Cells or on a Range or Table.

' last row containing data (using Find in formulas)
jLastRangeData = oSht.Range("NamedRange").Find(What:="*", LookIn:=xlFormulas, SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row
' last visible row containing data (using Find in values)
jLastVisibleRangeData = oSht.Range("NamedRange").Find(What:="*", LookIn:=xlValues, SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row
' last row containing data (using Find in formulas)
jLastTableData = oSht.ListObjects("Table1").Range.Find(What:="*", LookIn:=xlFormulas, SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row
' last visible row containing data (using Find in values)
jLastVisibleTableData = oSht.ListObjects("Table1").Range.Find(What:="*", LookIn:=xlValues, SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row

  • jLastRangeData returns 25
  • jLastVisibleRangeData returns 20
  • jLastTableData returns 25
  • jLastVisibleTableData returns 20

Methods using COUNT

Sometimes its simpler to just count the number of rows, add the starting row number and subtract 1.

‘ last cell in Named Range

jLastInRange = oSht.Range("NamedRange").Offset(oSht.Range("NamedRange").Rows.Count – 1, 0).Row

‘ last row in named range current region

jLastInRegion = oSht.Range("NamedRange").CurrentRegion.Rows.Count + oSht.Range("NamedRange").Row – 1

‘ last row in Table

jLastInTable = oSht.ListObjects("Table1").Range.Rows.Count + oSht.ListObjects("Table1").Range.Row – 1

‘ last data row in table (excludes total row)

jLastTableDataRow = oSht.ListObjects("Table1").ListRows.Count + oSht.ListObjects("Table1").Range.Row – 1

  • jLastInRange returns 30 (it counts the empty cells too)
  • jLastInRegion returns 25 (it excludes the bounding empty cells)
  • jLastInTable returns 25
  • jLastTableDataRow returns 24 (ListObject.ListRows excludes the total row and header row so I have not subtracted 1 for the header row)


I was really surprised to find that End(xlUP) worked differently for Tables than for Ranges.

And with Tables sometimes it seems best to work with a Range that represents the table rather than directly with ListRows: the syntax is not always obvious to me.

There are many different ways of finding End rows but mostly I use range.find as the most fool-proof method (but there are still snags with things like Merged cells).

What’s your most frequently used method?

Posted in Excel, Formatting, VBA | Tagged , | 9 Comments

Excel JavaScript API Part 5: The large numbers bug

There is currently (JavaScript Excel API set 1.4) a rather nasty bug when writing large integer numbers (anything larger than int32) back to a range.

30 January 2018 – API set 1.7 – this bug is still there!

The JS can correctly read these large numbers – it just silently gets the wrong answer when writing them back.

Testing what works and what does not work

I ran 5 tests:

  1. 9876543210 – a large integer
  2. 9876543210.0 – a large double that can convert to an integer
  3. 9876543210.1 – a large non-integer double
  4. ‘9876543210’ – a large number as a string
  5. “‘9876543210” – a large number as a string prefixed with ‘

The results were:

  1. 1286608618 – wrong
  2. 1286608618 – wrong
  3. 9876543210.1 – correct
  4. 9876543210 – gives a number but the string type has been ignored by Excel
  5. ‘9876543210 – correct – Excel treats this as string because of the ‘

Here is the test code:

async function run() {
try {
await (context) => {
let sheet = context.workbook.worksheets.getActiveWorksheet();
let rng1 = sheet.getRange("A3");
rng1.values = [[9876543210]];
let rng2 = sheet.getRange("A5");
rng2.values = [[9876543210.0]];
let rng3 = sheet.getRange("A7");
rng3.values = [[9876543210.1]];
let rng4 = sheet.getRange("A9");
rng4.values = [['9876543210']];
let rng5 = sheet.getRange("A11");
rng5.values = [["'9876543210"]];

await context.sync();
catch (error) {

The Hacky Bypass

The real problem of course comes when you use JS to read a range and write it back but you don’t know what the range contains. If it’s a large integer your code is FUBAR.

The only current bypass is to loop through the range values, test for large integers and convert them to string by surrounding with ‘.


I sure hope this gets fixed soon!

Posted in Excel, JS-API | Tagged , | 4 Comments

Excel JavaScript API Part 4: The shallow copy problem

I was trying to read the values from a Range and then write modified versions of the values to two different ranges. Should be straightforward:

async function setValue() {
try {
await (context) => {
let sheet = context.workbook.worksheets.getActiveWorksheet();
let rng1 = sheet.getRange("A1:A2").load("values");
await context.sync();
let rng2 = sheet.getRange("B4:b5");
let rng3 = sheet.getRange("B6:B7");
rng2.values = rng1.values;
rng3.values = rng1.values;
rng2.values[0][0] = rng2.values[0][0] + 0.9;
rng3.values[0][0] = rng3.values[0][0] + 0.01;
await context.sync();
catch (error) {

Well this does not work: both B4 and B6 have 0.91 added to them: wrong answer!

The reason this does not work is that JavaScript does something called “shallow copying” for objects and arrays. In effect this means that rng2 and rng3 are just different names for rng1: they all refer to the same set of values.

So when you change one variable you are actually changing them all!

Creating a real copy : “Deep Copying”

A “Deep Copy” is one where the values really are copied rather than just adding an extra name for the values. JQuery has a handy method for doing this: JQuery.extend ($ is short for JQuery)

// create deep copy of rng1
let deep1 = [];
$.extend(true, deep1, rng1.values);
// set rng2 = deep copy
rng2.values = deep1;

So now I can assign the deep copy to rng2.
But if I also assign the same deep copy to rng3 I am back in the same trap: rng2 and rng3 would just be different names for the deep copy!

So I need to either create another deep copy to use for rng3 or assign rng1 to rng3.
Of course then when I change rng3 I am also changing rng1 but that does not matter (although probably bad practice) because I am not returning rng1 back to the worksheet.
(rng1 never appears on the left of the = assignment)

async function setValue() {
try {
await (context) => {
let sheet = context.workbook.worksheets.getActiveWorksheet();
let rng1 = sheet.getRange("A1:A2").load("values");
await context.sync();
// create deep copy of rng1
let deep1 = [];
$.extend(true, deep1, rng1.values);
let rng2 = sheet.getRange("B4:b5");
let rng3 = sheet.getRange("B6:B7");
// set rng2 = deep copy
rng2.values = deep1;
// set rng3 = rng1
rng3.values = rng1.values;
rng2.values[0][0] = rng2.values[0][0] + 0.9;
rng3.values[0][0] = rng3.values[0][0] + 0.01;
await context.sync();
catch (error) {


Shallow copies are a wonderful JavaScript “Gotcha” for VBA programmers!

Posted in arrays, Excel, JS-API | Tagged , | 1 Comment

Excel JavaScript API Part 3: Benchmark of Processing Arrays Performance – Loop vs Reduce vs COUNTIFS vs VBA

In a previous post I compared several different ways of processing data with VBA. The fastest way was to get the data into a variant array and loop on it.

JavaScript has some powerful array methods so I wanted to see how they performed compared to VBA. I looked at four different ways of processing data using the JS API:

  • Get data into a JavaScript Array and loop
  • Get data into a JavaScript proxy Range object and loop
  • Get data into a JavaScript array and use the JS Reduce method
  • Call the worksheet function COUNTIFS from JavaScript

The Test Data

I am using the same test data as the previous post: 100000 rows with 2 columns.
Column A is randomly 50% populated with “X” and Column B is randomly 50% populated with “Y”.

The task is to count how many rows have an “X” in column A and a “Y” in column B in the same row.

Getting the data from Excel into a JavaScript array

This task is much slower than VBA: JavaScript takes around 290 milliseconds to read 100000 rows and 2 columns, but VBA takes only around 16 milliseconds.

Let’s ignore that and just focus on how efficient JavaScript is at processing arrays.

Benchmark Timings


If you ignore the time taken to get the data into the array then JavaScript and VBA are equally efficient – 19 milliseconds each.

I expected it to be faster to process the proxy range object directly rather than copying the data into an array and using that – but I was wrong. Looping directly on the proxy object is a lot slower than looping on an array derived from the proxy object.

Similarly I thought that the array Reduce method would be fast: but Reduce is slower than directly looping the array!

The overall winner in this case is COUNTIFS because the data never gets transferred to VBA or JavaScript so the extra 290 (JS) or 16 (VBA) milliseconds don’t get incurred. Calling a worksheet function from VBA also has a much smaller overhead than calling it from JS.

The JavaScript code

Here are the four different examples of the JavaScript code.

Looping the Array

The complete JavaScript code I am using for the looping the array method looks like this:

var t0;
var t1;
var t2;
$('#run').click(function () {
t0 =;
.then(() => {
t2 =;
console.log("Time to read data from XL " + Math.round(t1 - t0) + " milliseconds.")
console.log("Time to process array " + Math.round(t2 - t1) + " milliseconds.")

function invokeRun() {
return (context) {
var range1 = context.workbook.worksheets.getItem("Sheet1").getRange("A1:B100000").load('values');
return context.sync()
.then(() => {
var arr = range1.values;
t1 =;
var nFound = 0;
for (var j = 0; j < arr.length; j++) {
if (arr[j][0] === 'X') {
if (arr[j][1] === 'Y') nFound++;
console.log("XY pairs found " + nFound);

The invokeRun function loads the values from the range into a proxy range object using context.sync() , then creates a JavaScript array (actually an array of arrays) from the proxy object and loops down the array looking for an X and a Y in the same row.

Looping the Proxy Range Object

function invokeRun() {
return (context) {
var range1 = context.workbook.worksheets.getItem("Sheet1").getRange("A1:B100000").load('values');
return context.sync()
.then(() => {;
var nFound = 0;
for (var j = 0; j < range1.values.length; j++) {
if (range1.values[j][0] === 'X') {
if (range1.values[j][1] === 'Y') nFound++;

This version of InvokeRun loops directly on the proxy object values rather than on an array derived from the proxy object.

Using the REDUCE array method

This version of InvokeRun uses JavaScript’s REDUCE array method, where you supply an aggregating function to be applied to each row of the array.

function invokeRun() {
return (context) {
var range1 = context.workbook.worksheets.getItem("Sheet1").getRange("A1:B100000").load('values');
return context.sync()
.then(() => {
t1 =;
var arr = range1.values;
var nFound = arr.reduce(function (ct, currval, ix, arr) {
if (arr[ix][0] === 'X') {

if (arr[ix][1] === 'Y') {
return ct;
}, 0);

Using Worksheet Function COUNTIFS

This version demonstrates calling a worksheet function on the range. Since the range values never get passed across to JavaScript it is by far the fastest solution for this case!

function invokeRun() {
return (context) {
var rangeA = context.workbook.worksheets.getItem("Sheet1").getRange("A1:A100000");
var rangeB = context.workbook.worksheets.getItem("Sheet1").getRange("B1:B100000");
var count = context.workbook.functions.countIfs(rangeA, "X", rangeB, "Y");
return context.sync()
.then(() => {
t1 =;
console.log("XY pairs found " + count.value);

The VBA Code

For completeness sake here is the equivalent VBA code for the looping the array case.

Sub FindXY3()
Dim vArr As Variant
Dim j As Long
Dim n As Long
Dim dTime As Double
Dim dTime2 As Double
dTime2 = MicroTimer
vArr = Range("a1:B100000").Value2
dTime = MicroTimer
For j = LBound(vArr) To UBound(vArr)
If vArr(j, 1) = "X" Then
If vArr(j, 2) = "Y" Then
n = n + 1
End If
End If
Next j
Debug.Print "Var array " & n & " Get " & (dTime - dTime2) * 1000 & " Find " & (MicroTimer - dTime) * 1000
End Sub




JavaScript seems fairly efficient at processing arrays, and is very comparable to VBA.

The problem is the time taken to transfer data from Excel to JavaScript.

Of the JavaScript array methods bench-marked, Reduce and direct processing of the proxy object were slower than direct looping on an array.

Using a worksheet function such as COUNTIFS is considerably faster than looping an array as long as you can avoid transferring the data to VBA or JavaScript.


Posted in arrays, JS-API, VBA | Tagged , , | 4 Comments

Excel JavaScript API Part 2: Benchmark of Read/Write Range Performance

As an Excel Office Developer many of the Excel based applications I develop depend on reading data from Excel worksheet ranges, processing it and then writing the processed data back to a worksheet.

In VBA the way to do this is to read the ranges into variant arrays, loop through the arrays and then write them back. Done efficiently this kind of process can be reasonably fast even with large amounts of data.

So how do you do this kind of operation using the Excel JS-API and how does performance compare with VBA?

Note: these tests were done using JS-API release 1.4 with Office Insider Slow (1702.7870.2020). Further performance improvements may be introduced in later versions.

The Test Workbook

The test workbook has 500000 random numbers hard-coded into column A on Sheet1. The benchmark will read subsets of these numbers and then write them back to column D on Sheet1.

The set of subset volumes to be used in the benchmark are on Sheet2!B19:B25.


The VBA Benchmark Code

The VBA benchmark code reads the subset volumes to be used and then times reading and writing the data.

Option Explicit
Option Base 1
Private Declare Function getFrequency Lib "kernel32" _
Alias "QueryPerformanceFrequency" (cyFrequency As Currency) As Long
Private Declare Function getTickCount Lib "kernel32" _
Alias "QueryPerformanceCounter" (cyTickCount As Currency) As Long
Function MicroTimer() As Double
' Returns seconds.
Dim cyTicks1 As Currency
Static cyFrequency As Currency
' Initialize MicroTimer
MicroTimer = 0
' Get frequency.
If cyFrequency = 0 Then getFrequency cyFrequency
' Get ticks.
getTickCount cyTicks1
' Seconds = Ticks (or counts) divided by Frequency
If cyFrequency Then MicroTimer = cyTicks1 / cyFrequency
End Function

Sub VarBench()
Dim dT1 As Double
Dim dT2 As Double
Dim dT3 As Double
Dim rng1 As Range
Dim rng2 As Range
Dim var As Variant
Dim j As Long
Dim varIn As Variant
Dim varOut() As Variant
Application.ScreenUpdating = False
Application.Calculation = xlCalculationManual
varIn = ThisWorkbook.Worksheets("Sheet2").Range("B19:B25").Value2
ReDim varOut(1 To UBound(varIn), 1 To 2)
' initialise timer etc
dT1 = MicroTimer
For j = 1 To UBound(varIn)
dT1 = MicroTimer
Set rng1 = Worksheets("Sheet1").Range("A1").Resize(varIn(j, 1), 1)
Set rng2 = Worksheets("Sheet1").Range("D1").Resize(varIn(j, 1), 1)
var = rng1.Value2
dT2 = MicroTimer
rng2.Value2 = var
dT3 = MicroTimer
varOut(j, 1) = (dT2 - dT1) * 1000
varOut(j, 2) = (dT3 - dT2) * 1000
Next j
ThisWorkbook.Worksheets("Sheet2").Range("F19:G25").Value2 = varOut
Application.Calculation = xlCalculationAutomatic
End Sub

The JS API Code

Here is some basic JS (well actually its TypeScript) code to read 500000 cells into a JS range and then write it back to a different range:


async function run() {
try {
await (context) => {
let rngFrom = context.workbook.worksheets.getItem("Sheet1").getRange("A1:A500000").load("values");
await context.sync();
let rngTo = context.workbook.worksheets.getItem("Sheet1").getRange("D1:D500000");
rngTo.values = rngFrom.values;
await context.sync();
catch (error) {

This code is using the Typescript Async – Await pattern. The first Let statement identifies the sheet and range and queues the load of the values into the JS range array.
This statement only places a command into the command queue: it does NOT actually load the values. The next statement await context.sync() executes all the commands that are in the queue and actually gets the values.

Similarly the second Let statement identifies the range to be written to, and then the rngTo.Values=rngFrom.values statement queues a command to write the values back. The next statement await context.sync() executes the 2 commands that are in the queue.

So this is the basic JS API pattern using Typescript’s Async Await: it enables the code to be read and understood as though it is processing sequentially and synchronously just likeĀ  VBA.

The real value of this asynchronous queuing up of a batch of commands and controlling when to execute them comes when the code is executing online or accessing a server in the cloud.

So now lets look at the JS benchmark equivalent of the VBA code.

$('#run').click(function () {
function invokeRun() {
return function (context) {
// get number of cells array from worksheets
var actsheet=context.workbook.worksheets.getActiveWorksheet();
var cellsrange = actsheet.getRange("B19:B25").load("values");
// loop. on cells array
var j = 0;
var t0 = 0;
var t1 = 0;
var t2 = 0;
var range1;
var range2;
var range3;
var nCellsArr;

context.sync().then(function () {
nCellsArr = cellsrange.values;
// read and time requested number of cells
function task() {
t0 =;
range1 = context.workbook.worksheets.getItem("Sheet1").getRange("A1").getResizedRange(nCellsArr[j][0] - 1, 0).load("values");
return context.sync()
.then(function () {
t1 =;
// write back and time the cells just read
range2 = context.workbook.worksheets.getItem("Sheet1").getRange("D1").getResizedRange(nCellsArr[j][0] - 1, 0)
range2.values = range1.values;
return context.sync();
.then(function () {
t2 =;
// create array for timings
var millisecs = new Array(1);
// store timings in millisecs array
millisecs[0] = new Array();
millisecs[0][0] = (t1 - t0);
millisecs[0][1] = (t2 - t1);
// write timings back to sheet
range3 = context.workbook.worksheets.getItem("Sheet2").getRange("C19:D19").getOffsetRange(j, 0);
range3.values = millisecs;
return context.sync();
.then(function () {
if (j < 6) {
return task();
} else {
return context.sync();

return task();


This code is using the Javascript Promises syntax.

The main new things in this code are:

using for timings

using suspendCalculationUntilNextSync() to switch off calculation until the next context.sync() has processed the queue of commands.

Benchmark Results

I ran both the VBA benchmark and the JS API benchmark once in Manual calculation mode and once in Automatic calculation mode.



Note: If you don’t use suspendCalculationUntilNextSync then in Automatic calculation mode the Javascript triggers a recalculation once for every 1500 or so cells it writes. This has a drastic slowing down effect!


As expected writing data back to Excel is considerably slower than reading data.

JavaScript read is between 20 and 200 times slower than VBA, and it looks like there is a much higher JS overhead per read than VBA.

JavaScript write is between 10 and 15 times slower than VBA, but the overhead looks much more comparable.





Posted in arrays, Calculation, JS-API, VBA | Tagged , , | 1 Comment

Excel Range.Value(ValueType): What is this parameter?

Whilst visiting Microsoft Research in Cambridge I was chatting to fellow MVP Roger Govier. He mentioned that he was using this strange parameter to the Range.Value (ValueType) method, which I had been meaning to look at for a long time since it was added in Excel 2007.

So I promised him a blog post!


The first thing to do is look at Excel VBA Help.

xlRangeValueDefault 10 Default. If the specified Range object is empty, returns the value Empty (use the IsEmpty function to test for this case). If the Range object contains more than one cell, returns an array of values (use the IsArray function to test for this case).
xlRangeValueMSPersistXML 12 Returns the recordset representation of the specified Range object in an XML format.
xlRangeValueXMLSpreadsheet 11 Returns the values, formatting, formulas, and names of the specified Range object in the XML Spreadsheet format.

Unfortunately that did not really leave me any the wiser. So lets try looking at some values using the VBE Immediate and Locals windows.

I am using some very simple data, a mixture of strings and numbers:


And some very simple code

Sub CopyWithFormat2()
Dim var As Variant
Dim j As Long
var = Range("A8:A11").Value(xlRangeValueDefault)
Range("C8:C11").Value(xlRangeValueDefault) = var
End Sub

But this changes all textual numbers to real numbers and dates!


If you change xlRangeValueDefault (10) to xlRangeValueXMLSpreadsheet (11) you get the unchanged textual numbers.


Looking at var in the immediate window this is what it contains:

<?xml version=”1.0″?>
<?mso-application progid=”Excel.Sheet”?>
<Workbook xmlns=”urn:schemas-microsoft-com:office:spreadsheet”
<Style ss:ID=”Default” ss:Name=”Normal”>
<Alignment ss:Vertical=”Bottom”/>
<Font ss:FontName=”Calibri” x:Family=”Swiss” ss:Size=”11″ ss:Color=”#000000″/>
<Worksheet ss:Name=”Sheet1″>
<Table ss:ExpandedColumnCount=”1″ ss:ExpandedRowCount=”4″
<Cell><Data ss:Type=”String” x:Ticked=”1″>011</Data></Cell>
<Cell><Data ss:Type=”Number”>11</Data></Cell>
<Cell><Data ss:Type=”String” x:Ticked=”1″>11</Data></Cell>
<Cell><Data ss:Type=”String” x:Ticked=”1″>1-11</Data></Cell>

So this is fine unless you want to do some processing of the data in var!

If you use xlRangeValueMSPersistXML (12) then you get an “Object doesn’t support this action” error message when you try to put var back on the worksheet.

And the immediate window shows this as the contents of var: looks like some kind of pivot cache format.

<xml xmlns:x=”urn:schemas-microsoft-com:office:excel”
xmlns:rs=”urn:schemas-microsoft-com:rowset” xmlns:z=”#RowsetSchema”>
<s:Schema id=”RowsetSchema”>
<s:ElementType name=”row” content=”eltOnly”>
<s:attribute type=”Col1″/>
<s:extends type=”rs:rowbase”/>
<s:AttributeType name=”Col1″ rs:name=” 011″>
<s:datatype dt:maxLength=”255″/>
<z:row Col1=”11″/>
<z:row Col1=”11″/>
<z:row Col1=”1-11″/>


Well: I can’t actually see a scenario in which I could find a use for this!

Have you ever used this in anger?

Any ideas for scenarios where it would be useful?




Posted in Formatting, VBA | Tagged , | 8 Comments