function parseRegExp(value) {
  if (value) {
    return new RegExp(value.replace(/^\/(.*)\/$/, '$1'));
  }
}
JSON does not support regexes, so, e.g., JSON.parse() will not create
a RegExp from the JSON value `[ "/matchString/" ]`, which is
technically just an array containing a string that begins and end with
a forward slash. To get a RegExp from a JSON string, it must be
constructed explicitly in JavaScript.

The likelihood of actually wanting to match text that is enclosed in
forward slashes is probably quite rare, so if forward slashes were
included in an argument that requires a regex, the user most likely
thought they were part of the syntax for specifying a regex.

In the unlikely case that forward slashes are indeed desired in the
search string, the user would need to enclose the expression in a
second set of slashes:

   --customAttrSrround "[\"//matchString//\"]"