parser: escape js template literal syntax inside <script> tags (#9738)

vlib/v/parser/tmpl.v

@@ -214,11 +214,15 @@ mut sb := strings.new_builder($lstartlength)\n
 			} else {
 				source.writeln('</div>')
 			}
+		} else if state == .js {
+			// replace `$` to `\$` at first to escape JavaScript template literal syntax
+			source.writeln(line.replace(r'$', r'\$').replace(r'$$', r'@').replace(r'.$',
+				r'.@').replace(r"'", r"\'"))
 		} else {
 			// HTML, may include `@var`
 			// escaped by cgen, unless it's a `vweb.RawHtml` string
-			source.writeln(line.replace('@', '$').replace('$$', '@').replace('.$', '.@').replace("'",
-				"\\'"))
+			source.writeln(line.replace(r'@', r'$').replace(r'$$', r'@').replace(r'.$',
+				r'.@').replace(r"'", r"\'"))
 		}
 	}
 	source.writeln(parser.tmpl_str_end)

vlib/v/tests/inout/file.html

@@ -17,6 +17,9 @@ color: red;
 </script>
 <script>
 document.getElementById("demo").innerHTML = "Hello JavaScript!";
+
+const classes = `header ${ isLargeScreen() ? '' :
+`icon-${item.isCollapsed ? 'expander' : 'collapser'}` }`;
 </script>
 </head>
 

vlib/v/tests/inout/tmpl_parse_html.out

@@ -17,6 +17,9 @@ color: red;
 </script>
 <script>
 document.getElementById("demo").innerHTML = "Hello JavaScript!";
+
+const classes = `header ${ isLargeScreen() ? '' :
+`icon-${item.isCollapsed ? 'expander' : 'collapser'}` }`;
 </script>
 </head>