Illegal invocation on transport file

Since April 9th I started seeing errors that I can’t reproduce reaching my users and it seems be more frequently.

I’m using @datadog/browser-rum 2.7.1 which depends on @datadog/browser-core 2.7.1

The raw error is:

TypeError: Illegal invocation
  at e.send(../../../src/transport/transport.ts:22:34)
  at e.flush(../../../src/transport/transport.ts:68:20)
  at apply(../../../src/transport/transport.ts:153:12)
  at n(../../src/helpers.ts:87:17)

Line 22 on the source map is:

    HttpRequest.prototype.send = function (data, size) {
        var url = this.withBatchTime ? addBatchTime(this.endpointUrl) : this.endpointUrl; // <== this one
        if (navigator.sendBeacon && size < this.bytesLimit) {
            var isQueued = navigator.sendBeacon(url, data);
            if (isQueued) {
                return;
            }

On file @datadog/browser-core/esm/transport/transport.js.

But this does not seem to make sense as the error is e.send so it is happening when send is called.

It seems to happen in any browser (Chrome 70/79/80/89, Mobile Safari, Samsung Internet, Chrome Mobile are some examples). I could not reproduce it yet.

Any thoughts or ideas are welcome.

[bcaudan]

the two linked PRs has been released in 2.7.4, let us know how it goes

[BenoitZugmeyer]

@igrayson: In your screenshot, we can see that the exception is triggered at a place where window.navigator.sendBeacon is used followed by a window.fetch fallback, which is not done in our codebase. So, this is not the same issue, and probably not related to the RUM Browser SDK (as it does not instrument navigator nor sendBeacon)