How can I debug eslint rules?

Question

I wanted to debug eslint rules for performance optimization. Is there any way I can debug it using browser/command-line/tool?

Answer 1

You can use TIMING=1 when running on the command line:

$ TIMING=1 eslint lib

Rule                    | Time (ms) | Relative
:-----------------------|----------:|--------:
no-multi-spaces         |    52.472 |     6.1%
camelcase               |    48.684 |     5.7%
no-irregular-whitespace |    43.847 |     5.1%
valid-jsdoc             |    40.346 |     4.7%
handle-callback-err     |    39.153 |     4.6%
space-infix-ops         |    35.444 |     4.1%
no-undefined            |    25.693 |     3.0%
no-shadow               |    22.759 |     2.7%
no-empty-class          |    21.976 |     2.6%
semi                    |    19.359 |     2.3%

Documentation: https://eslint.org/docs/1.0.0/developer-guide/working-with-rules#per-rule-performance