Choosing more files on Combine files into one PDF now appends to the queue instead of replacing it.

Date: 2026-09-06 15:52 Summary: Choosing more files on Combine files into one PDF now appends to the queue instead of replacing it. Visibility: people

[question] http://127.0.0.1:8788/zh/tools/combine-files-into-one-pdf 选择文件添加后，不要清空原来的已经选择添加的文件，依赖用户主动清空或者手动删除

Tool links (English)

https://onlinefreetools.org/tools/combine-files-into-one-pdf Chinese: https://onlinefreetools.org/zh/tools/combine-files-into-one-pdf

[try to solve]

Context

The Combine files into one PDF tool already kept a client-side queue with per-item Move up / Move down / Remove and a Clear button. A second Choose files (or drop) still wiped that queue, so users who picked PDFs from different folders lost the first batch.

Process

Read src/pages/combineFilesIntoOnePdfPage.ts and found addFiles() doing items = [] before load, then items = loaded.filter(Boolean) after Promise.all.
Compared sibling tools. mergePdfPage.ts and imagesToPdfPage.ts append with items.push(...). Native <input type="file"> also replaces its FileList on every change; the page already reset fileInput.value = '' after change so the same files can be chosen again, but the in-memory queue still replaced.
Changed addFiles to items.concat(added). Empty-queue error now runs only when the combined list is still empty. Size warning sums every queued item’s bytes.byteLength.
Added queueEpoch, incremented in clearAll, so a Clear click during an in-flight read drops the stale callback instead of putting deleted files back.
Left Sample as a reset: loadSample() still calls clearAll first. Remove and Clear remain the only ways to drop existing items.
Prerendered this slug, gzipped, seeded local R2, then cleared the persisted Worker Cache API under .wrangler/state/v3/cache so http://127.0.0.1:8788/zh/tools/combine-files-into-one-pdf served the new script. Playwright: after Clear, add keep-a.pdf then keep-b.pdf → both stay; Remove first item → keep-b.pdf; Clear → empty list.

Root cause / analysis

<input type="file" multiple> does not accumulate. The page copied that replace semantics into items. Merge-style tools should treat Choose files as “add more”; replacement belongs on Clear / per-item Remove (and Sample, which is an explicit reset).

Solution

addFiles appends. Clear / Remove / Sample still empty the queue. After a local Cache API HIT of the old HTML, delete the persisted cache directory or purge the URL; bumping PAGES_CACHE_VERSION is for a real release, not this fix.

Notes / boundaries

Adding files after the auto sample keeps the sample PDFs until the user Clears or Removes them.
Unsupported types are still skipped. If nothing valid is added and the queue was already empty, the empty error still shows.
Isolation lint on this slug fails because the working tree already contains unrelated vendor and docs changes; this edit is only the combine-files page plus its catalog updatedAt.

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