mirror of
https://github.com/typeorm/typeorm.git
synced 2025-12-08 21:26:23 +00:00
bbdc20f8ca
Digging further into #3857. See also #8955, #8956. As [previously discussed](https://github.com/typeorm/typeorm/issues/3857#issuecomment-699505893), the query builder currently suffers from poor performance in two ways: quadratic numbers of operations with respect to total table/column counts, and poor constant factor performance (regexps can be expensive to build/run!) The constant-factor performance is the more tractable problem: no longer quadratically looping would be a chunky rewrite of the query builder, but we can locally refactor to be a bunch cheaper in terms of regexp operations. This change cuts the benchmark time here in ~half (yay!). We achieve this by simplifying the overall replacement regexp (we don't need our column names in there, since we already have a plain object where they're the keys to match against) so compilation of that is much cheaper, plus skipping the need to `escapeRegExp` every column as a result.