[GSOC][PATCH v2]userdiff: improve code quality and add JavaScript language driver.

[Sergius Nyah <sergiusnyah@gmail.com>]

This commit introduces several improvements to the codebase:

- replace the use of `test_i18ngrep` with `test_grep` in
`t/t4018-diff-funcname.sh` for better pattern matching and improved
performance.
- add a JavaScript language driver to enhance the functionality of the
application.
- clean up the code by removing trailing whitespaces and fix multiline
comments in `t/t4034-diff-words.sh` and `userdiff.c`.

Signed-off-by: Sergius Nyah <sergiusnyah@gmail.com>
---
 t/t4018-diff-funcname.sh | 14 +++++++-------
 t/t4034-diff-words.sh    |  1 +
 userdiff.c               | 23 ++++++++++++-----------
 3 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/t/t4018-diff-funcname.sh b/t/t4018-diff-funcname.sh
index d35cce18a0..e6d2f1c215 100755
--- a/t/t4018-diff-funcname.sh
+++ b/t/t4018-diff-funcname.sh
@@ -119,8 +119,6 @@ do
 	"
 done

-test_done
-
 test_expect_success 'identify builtin patterns in JavaScript' '
 	# setup
 	echo "function myFunction() { return true; }" > test.js &&
@@ -136,9 +134,11 @@ test_expect_success 'identify builtin patterns in JavaScript' '
 	git diff >output &&

 	# check results
-	test_i18ngrep "function myFunction() { return true; }" output &&
-	test_i18ngrep "function myFunction() { return false; }" output &&
-	test_i18ngrep "var myVar = function() { return false; }" output &&
-	test_i18ngrep "var myVar = function() { return true; }" output
+	test_grep "function myFunction() { return true; }" output &&
+	test_grep "function myFunction() { return false; }" output &&
+	test_grep "var myVar = function() { return false; }" output &&
+	test_grep "var myVar = function() { return true; }" output
 '
-test_done
\ No newline at end of file
+
+test_done
+
diff --git a/t/t4034-diff-words.sh b/t/t4034-diff-words.sh
index 74586f3813..cf2374af2c 100755
--- a/t/t4034-diff-words.sh
+++ b/t/t4034-diff-words.sh
@@ -328,6 +328,7 @@ test_language_driver dts
 test_language_driver fortran
 test_language_driver html
 test_language_driver java
+test_language_driver javascript
 test_language_driver kotlin
 test_language_driver matlab
 test_language_driver objc
diff --git a/userdiff.c b/userdiff.c
index bbe2bcb9a3..15342c8662 100644
--- a/userdiff.c
+++ b/userdiff.c

 PATTERNS("javascript",
-      /* Looks for lines that start with optional whitespace, followed
-      * by 'function'* and any characters (for function declarations),
-      * or valid JavaScript identifiers, equals sign '=', 'function' keyword
-      * and any characters (for function expressions).
-      * Also considers functions defined inside blocks with '{...}'.
-      */
-      "^[ \t]*(function[ \t]*.*|[a-zA-Z_$][0-9a-zA-Z_$]*[ \t]*=[ \t]*function[ \t]*.*|(\\{[ \t]*)?)\n",
-      /* This pattern matches JavaScript identifiers */
-      "[a-zA-Z_$][0-9a-zA-Z_$]*"
-      "|[-+0-9.eE]+|0[xX][0-9a-fA-F]+"
-      "|[-+*/<>%&^|=!:]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\|"),
+	/*
+	 * Look for lines that start with optional whitespace, followed
+	 * by 'function' and any characters (for function declarations),
+	 * or valid JavaScript identifiers, equals sign '=', 'function' keyword
+	 * and any characters (for function expressions).
+	 * Also consider functions defined inside blocks with '{...}'.
+	 */
+	 "^[ \t]*(function[ \t]*.*|[a-zA-Z_$][0-9a-zA-Z_$]*[ \t]*=[ \t]*function[ \t]*.*|(\\{[ \t]*)?)\n",
+	 /* Match JavaScript identifiers with this pattern */
+	 "[a-zA-Z_$][0-9a-zA-Z_$]*"
+	 "|[-+0-9.eE]+|0[xX][0-9a-fA-F]+"
+	 "|[-+*/<>%&^|=!:]=|--|\\+\\+|<<=?|>>=?|&&|\\|\\|"),

2.43.2