test: fix RegExp nits

* Remove needless RegExp flag

  In fixed case, `/g` flag is needless in the boolean context.

* Remove needless RegExp capturing

  Use non-capturing grouping or remove capturing completely when:

  * capturing is useless per se, e.g. in test() check;
  * captured groups are not used afterward at all;
  * some of the later captured groups are not used afterward.

* Use test, not match/exec in boolean context

  match() and exec() return a complicated object,
  unneeded in a boolean context.

* Do not needlessly repeat RegExp creation

  This commit takes RegExp creation out of cycles and other repetitions.

  As long as the RegExp does not use /g flag and match indices,
  we are safe here.

  In tests, this fix hardly gives a significant performance gain,
  but it increases clarity and maintainability,
  reassuring some RegExps to be identical.

  RegExp in functions are not taken out of their functions:
  while these functions are called many times
  and their RegExps are recreated with each call,
  the performance gain in test cases
  does not seem to be worth decreasing function self-dependency.

PR-URL: https://github.com/nodejs/node/pull/13770
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/test/sequential/test-process-warnings.js b/test/sequential/test-process-warnings.js
index 0ab8652f56..944029d8b3 100644
--- a/test/sequential/test-process-warnings.js
+++ b/test/sequential/test-process-warnings.js
@@ -10,24 +10,26 @@ const normal = [warnmod];
 const noWarn = ['--no-warnings', warnmod];
 const traceWarn = ['--trace-warnings', warnmod];
 
+const warningMessage = /^\(.+\)\sWarning: a bad practice warning/;
+
 execFile(node, normal, function(er, stdout, stderr) {
   // Show Process Warnings
   assert.strictEqual(er, null);
   assert.strictEqual(stdout, '');
-  assert(/^\(.+\)\sWarning: a bad practice warning/.test(stderr));
+  assert(warningMessage.test(stderr));
 });
 
 execFile(node, noWarn, function(er, stdout, stderr) {
   // Hide Process Warnings
   assert.strictEqual(er, null);
   assert.strictEqual(stdout, '');
-  assert(!/^\(.+\)\sWarning: a bad practice warning/.test(stderr));
+  assert(!warningMessage.test(stderr));
 });
 
 execFile(node, traceWarn, function(er, stdout, stderr) {
   // Show Warning Trace
   assert.strictEqual(er, null);
   assert.strictEqual(stdout, '');
-  assert(/^\(.+\)\sWarning: a bad practice warning/.test(stderr));
+  assert(warningMessage.test(stderr));
   assert(/at Object\.<anonymous>\s\(.+warnings\.js:3:9\)/.test(stderr));
 });