Just seems to lock up after approx 6k rows.

[nick227]

No description provided.

[elwerene]

you should check out my fork, I optimized this a lot!

[ctavan]

@functionscope @elwerene Are there any plans to backport the enhancements from excel-export-fast into this project?

[emavok]

The largest performance improvement (which is getting the /Large example to work) is to the shareStrings from an Array to a Map (=object).

The function addStringCol does a lookup in shareStrings to see, whether the value is already registered as a shared string. In the example this lookup always fails (because it writes GUIDs) and hence is always looping over the entire array. A map lookup (shareStrings[value] === undefined) changes this lookup from an order n orperation to an log(n) operation. Since addStringCol is called for each string, the total execution time performs like O(n^2). With the map, it reduces to O(n log(n)).

Obviously, you have to count your sharedStrings manually. But the change is minimal, the result is huge. See attached file for the changes (marked by CHANGE START ... CHANGE END).
index.zip