Category Archives: JS-API

Develop Excel Conference

The 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 … Continue reading

Posted in .NET, arrays, Excel, JS-API, UDF, VBA, XLL | Leave a comment

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 … Continue reading

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: Well this does not work: both B4 and B6 have 0.91 added to them: wrong … Continue reading

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 … Continue reading

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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 … Continue reading

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

Excel JavaScript API Part 1: Overview & Comparison

I have been spending time in the last few months experimenting with the new JavaScript Excel API. This is the first of a planned series of posts examining the JS-API from the point of view of an Excel Office developer. … Continue reading

Posted in .NET, JS-API, UDF, Uncategorized, VBA, XLL | Tagged , , , , | 8 Comments