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, 3 insertions, 2 deletions

diff --git a/test/parallel/test-icu-punycode.js b/test/parallel/test-icu-punycode.js
index 13db2dd7ba..9488568267 100644
--- a/test/parallel/test-icu-punycode.js
+++ b/test/parallel/test-icu-punycode.js
@@ -24,6 +24,8 @@ const wptToASCIITests = require('../fixtures/url-toascii.js');
 }
 
 {
+  const errMessage = /^Error: Cannot convert name to ASCII$/;
+
   for (const [i, test] of wptToASCIITests.entries()) {
     if (typeof test === 'string')
       continue; // skip comments
@@ -33,8 +35,7 @@ const wptToASCIITests = require('../fixtures/url-toascii.js');
       caseComment += ` (${comment})`;
     if (output === null) {
       assert.throws(() => icu.toASCII(input),
-                    /^Error: Cannot convert name to ASCII$/,
-                    `ToASCII ${caseComment}`);
+                    errMessage, `ToASCII ${caseComment}`);
       assert.doesNotThrow(() => icu.toASCII(input, true),
                           `ToASCII ${caseComment} in lenient mode`);
     } else {