@dgkit/blob-saver

A tiny, framework-free helper for triggering a browser download from a Blob — the "create an object URL, click a hidden <a download>, clean up" dance every app ends up hand-rolling for CSV/Excel exports, generated PDFs, file previews saved to disk, etc.

const csv = new Blob([content], { type: 'text/csv' });
downloadBlob('report.csv', csv);

• ✅ No memory leaks — revokes the object URL after the download starts, unlike the common hand-rolled version that never calls URL.revokeObjectURL at all
• ✅ Framework-agnostic — zero dependencies, works anywhere JavaScript runs in a browser (Angular, React, Vue, plain DOM)
• ✅ Cleans up its temporary <a> element even if click() throws
• ✅ isDownloadSupported() to guard the call in environments without a DOM

Installation

yarn add @dgkit/blob-saver

Compatibility

Framework-agnostic. @dgkit/blob-saver has no Angular — or any framework — dependency. It is pure TypeScript with zero runtime dependencies, so it works with any Angular version (or React, Vue, plain Node… anywhere JavaScript runs).

Usage

import { downloadBlob } from '@dgkit/blob-saver';

function exportReport(rows: Row[]): void {
  const csv = new Blob([toCsv(rows)], { type: 'text/csv' });
  downloadBlob('report.csv', csv);
}

Guard it in code that might run outside a browser (e.g. during SSR):

import { downloadBlob, isDownloadSupported } from '@dgkit/blob-saver';

if (isDownloadSupported()) {
  downloadBlob('report.csv', csv);
}

API

downloadBlob(filename, blob)

Triggers a browser download of blob, saved as filename.

Creates a temporary object URL and an off-screen <a download>, clicks it, then removes the element and revokes the URL. The revoke is deferred to a macrotask so the browser has already started the download by the time the URL is released — calling URL.revokeObjectURL synchronously right after click() is a common reason hand-rolled versions of this function occasionally fail to download.

Throws if called where downloads aren't possible (see isDownloadSupported below) — this is an imperative, user-triggered action with no meaningful non-browser behavior.

isDownloadSupported()

Returns whether triggering a download is possible in the current environment — false under SSR/Node, or in any environment missing document or URL.createObjectURL.

Development

This package lives in the dgkit Nx monorepo.

yarn nx build blob-saver        # ng-packagr production build
yarn nx test blob-saver         # Vitest + coverage
yarn nx lint blob-saver         # ESLint
yarn nx typecheck blob-saver    # tsc --noEmit

Contributing

Contributions are welcome — see the repository CONTRIBUTING guide.

License

MIT