One idea to implement a spreadsheet in html and javascript.
- proof-of-concept code quality
- no error handling whatsoever (i.e. cycles in the sheet are not detected, erroneous formulas are not reported, etc.)
- doesn't support more than 26 columns (i.e. it can handle only A..Z columns, AA, AB, and so forth are not supported)
- written in pure js, no dependencies
Look in the source, it's very simple really.
Any onchange event in any cell causes recomputation of all cells.
If cell's input starts with =, it's parsed as a formula. Any <letter><digit>
in the string is replaced with a function call to compute that particular cell
formula. Once all the string replacements are done, an eval is called on the string.
- add cycles' detection, so user can't exceeded stack size by running too much recursion
- add caching so not all formulas have to be recomputed on each change
- support detecting invalid formulas
- make it work without element ids and support multiple sheets on one page
- add support for mathematical functions like users are used to from spreadsheet
software (e.g.
=POWER()instead of currentlyMath.pow(), and so on)