How to get file name from content-disposition

Here is how I used it sometime back. I'm assuming you are providing the attachment as a server response.

I set the response header like this from my REST service response.setHeader("Content-Disposition", "attachment;filename=XYZ.csv");

function(response, status, xhr){
    var filename = "";
    var disposition = xhr.getResponseHeader('Content-Disposition');
    if (disposition && disposition.indexOf('attachment') !== -1) {
        var filenameRegex = /filename[^;=\n]*=((['"]).*?\2|[^;\n]*)/;
        var matches = filenameRegex.exec(disposition);
        if (matches != null && matches[1]) { 
          filename = matches[1].replace(/['"]/g, '');
        }
    }
}

EDIT: Editing the answer to suit your question- use of the word inline instead of attachment

function(response, status, xhr){
    var filename = "";
    var disposition = xhr.getResponseHeader('Content-Disposition');
    if (disposition && disposition.indexOf('inline') !== -1) {
        var filenameRegex = /filename[^;=\n]*=((['"]).*?\2|[^;\n]*)/;
        var matches = filenameRegex.exec(disposition);
        if (matches != null && matches[1]) { 
          filename = matches[1].replace(/['"]/g, '');
        }
    }
}

More here

This is an improvement on marjon4's answer.

A much simplified way to the selected answer would be to use split like this;

var fileName = xhr.getResponseHeader('content-disposition').split('filename=')[1].split(';')[0];

Note: This solution may not work as expected if your file name itself contains a semi-colon (;)

In my case the header looks like this:

attachment; filename="test-file3.txt"

Therefore I was able to extract the filename pretty easily with a named group regexp:

const regExpFilename = /filename="(?<filename>.*)"/;

const filename: string | null = regExpFilename.exec(contentDispositionHeader)?.groups?.filename ?? null;

I know I'm slightly off topic here as OP doesn't have the quotes around the filename but still sharing in case someone comes across the same pattern as I just did

Or simply just:

var fileName = xhr.getResponseHeader('Content-Disposition').split("filename=")[1];