AngularJS, Regex causes error in test - angularjs

Question

When the user enters a specific expression, it gets translated to a button in the view.
Here is the code:
scope.buttonmaker = function(haystack) {
needle = /argumentation-link_to\((\d+),\s([\w\sÀ-ž]+)\)/;
return $sce.trustAsHtml(haystack.replace(new RegExp(needle, 'gi'), function(match) {
return '<button ng-click="goToArgumentation(' + needle.exec(match)[1] + ', 2, 3, false)" class="btn btn-md btn-info"> ' + needle.exec(match)[2] + '</button>'
}));
};
The code works, as it should and it also captures more than one expression, that match the Regex and the buttons are made correctly.
However, when running a test, this error happens:
Error: Cannot supply flags when constructing one RegExp from another.
RegExp#[native code]
buttonmaker#http://127.0.0.1:46071/assets/application-a2e90460a4bfb22fd82a11fde4c3041112d7349933767571c5e4928ad1951bdb.js:56321:68
fn
Looking at this stackoverflow-question, I first thought, that I did make a spelling mistake, so I tried this:
needle = "argumentation-link_to\((\d+),\s([\w\sÀ-ž]+)\)";
No errors occur, but the buttons weren't made.
Then, I tried this:
needle = /argumentation-link_to\((\d+),\s([\w\sÀ-ž]+)\)/gi
return $sce.trustAsHtml(haystack.replace(needle, function(match) {
return '<button ng-click="goToArgumentation(' + needle.exec(match)[1] + ', 2, 3, false)" class="btn btn-md btn-info"> ' + needle.exec(match)[2] + '</button>'
}));
This error occurs:
Error: needle.exec(...) is null
After looking at this stackoverflow-question, I believe, I have to somehow iterate over my text, but I don't know how to do it in my case.
Can someone help me to correct the code, so it does work in tests too?
EDIT:
When I do this:
needle = /argumentation-link_to\((\d+),\s([\w\sÀ-ž]+)\)/;
return $sce.trustAsHtml(haystack.replace(needle, function(match) {
return '<button ng-click="goToArgumentation(' + needle.exec(match)[1] + ', 2, 3, false)" class="btn btn-md btn-info"> ' + needle.exec(match)[2] + '</button>'
}));
No errors occur, but ONLY the first button gets made. This is obvious, because the global flag is missing.
And since the code works outside of tests, I think, the problem is more about the flags than the constructor.

Answer 1

I found a cheap fix, which requires not too much maintenance-work:
needle = /argumentation-link_to\((\d+),\s([\w\sÀ-ž]+)\)/gi
needle2 = /argumentation-link_to\((\d+),\s([\w\sÀ-ž]+)\)/
return $sce.trustAsHtml(haystack.replace(needle, function(match) {
return '<button ng-click="goToArgumentation(' + needle2.exec(match)[1] + ', 2, 3, false)" class="btn btn-md btn-info"> ' + needle2.exec(match)[2] + '</button>'
}));