CSV database class

A JS class that would use a file to CRUD CSV records:

CSV supports new lines and commas and double-double quotes, escaped inside double quote delimited blocks
one can create/open a file with a list of column headers and a column for a unique identifier
if the file exists, the first line of the file will be compared against the column headers and an error thrown if different
if file does not exist, the header line will be created
when first opening the file and changing it, cache:
- file update timestamp
- unique index, position of each line
on change, always check the timestamp of the file has not changed, throw an error if it has
on read by index, just read the line with position in a buffer of fixed length. if you cannot find the end of the line, just load another buffer and continue
- although here a maximum reasonable buffer like 65536 would be enough
on insert, just append the line at the end
on update:
- if the length of the new line is smaller than the existing one, just overwrite it and fill rest with blanks
- if the length is larger, delete the line and insert the new one
on delete, fill the entirety of the line with blanks
add a defragmentation method to rewrite the file in place and remove empty space

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