m.has is not a function

Hi, Thanks for putting the code out there, it's just what I'm looking for.

When I run a minified production build of my code I'm getting an error message in TraceError code:

m.has is not a function TypeError: m.has is not a function

this occurs at:

    key: "_defineProperty",
    value: function(e, t) {
        var a = m.has(this) ? m.get(this) : {};
        a[e] = t,
        m.set(this, a)
      } 

Is this a known error? Any work-arounds?
Thanks.

Start by reproducing the reported error in a minified production build and tracing the shown _defineProperty code back to its source in TraceError.js. Compare the production and non-minified builds to identify why m.has is not callable; the issue is done when the production build runs without this error and the behavior is covered by a verified reproduction.