How to open PDF blob from AJAX response in a new Chrome window

Question

I'm xhr-POSTing some data to a server, who returns a PDF, which I handle as a blob (using iron-ajax 's handle-as="blob" attribute, for the sake of completeness).
Now I want to display this blob/PDF in a new browser window (Chrome/Windows only).

I have already tried URL.createObjectURL(blob) and (new FileReader()).readAsDataURL(blob) -- both fail silently:

Method 1)

function handlePdfResponse(blob) {
    const pdfUrl = URL.createObjectURL(blob);
    window.open(pdfUrl, '_blank');
}

Method 2)

function handlePdfResponse(blob) {
    const reader = new FileReader();
    reader.onloadend = function(e) {
        window.open(reader.result, '_blank');
    };
    reader.readAsDataURL(blob);
}

In both cases, logging the input blob yields:

Blob {size: 219478, type: "application/pdf"}

Using the latter method, I can log the reader.result (which is a valid data-uri), paste it into a new Chrome window and gaze upon my shiny PDF.

There doesn't seem to be a way to debug either of these methods.

Thoughts?
Obvious errors?
Anything else I can try?

EDIT: Dear future generations: I'm on Chrome version 55.0

Answer 1

Turns out Chrome hates pop-ups. Unblock them for the win.