Puppeteer: Cannot accept FileChooser which is already handled!

A file chooser was already accepted or cancelled.

Error message

Cannot accept FileChooser which is already handled!

How this error happens

A file chooser can be accepted or cancelled only once. The second operation below reuses a chooser that has already finished.

The snippets use an open Puppeteer page named page.

await page.setContent(
    '<input id="upload" type="file">'
);

const [chooser] = await Promise.all([
    page.waitForFileChooser(),
    page.click("#upload"),
]);

await chooser.accept([]);

await chooser.accept([]);

How to fix

Wait for a new chooser before the click, then handle that chooser once.

const [chooser] = await Promise.all([
    page.waitForFileChooser(),
    page.click("#upload"),
]);

await chooser.accept([
    "/absolute/path/report.csv",
]);

Things to keep in mind

The fix requires an existing file at the supplied path. If the file input is accessible, ElementHandle.uploadFile avoids owning a chooser event. Empty accept([]) in the failing example only demonstrates the handled state.

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