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, 4 deletions

diff --git a/test/parallel/test-fs-read-stream-throw-type-error.js b/test/parallel/test-fs-read-stream-throw-type-error.js
index bc1fca3a3c..6e4f405daa 100644
--- a/test/parallel/test-fs-read-stream-throw-type-error.js
+++ b/test/parallel/test-fs-read-stream-throw-type-error.js
@@ -19,15 +19,16 @@ assert.doesNotThrow(function() {
   fs.createReadStream(example, {encoding: 'utf8'});
 });
 
+const errMessage = /"options" must be a string or an object/;
 assert.throws(function() {
   fs.createReadStream(example, 123);
-}, /"options" must be a string or an object/);
+}, errMessage);
 assert.throws(function() {
   fs.createReadStream(example, 0);
-}, /"options" must be a string or an object/);
+}, errMessage);
 assert.throws(function() {
   fs.createReadStream(example, true);
-}, /"options" must be a string or an object/);
+}, errMessage);
 assert.throws(function() {
   fs.createReadStream(example, false);
-}, /"options" must be a string or an object/);
+}, errMessage);