IndexedDB 数据压缩存储与透明解压实践

概述压缩存储可降低本地体积。本文提供写入压缩与读取解压的端到端示例。写入压缩与读取解压function openDB(name) { return new Promise((resolve, reject) => { const r = indexedDB.open(name, 1); r.onupgradeneeded = () => { const db = r.result; if (!db.objectStoreNames.contains('data')) db.createObjectStore('data', { keyPath:'id' }); }; r.onsuccess = () => resolve(r.result); r.onerror = () => reject(r.error); }); }

async function gzipText(text) { const cs = new CompressionStream('gzip'); const stream = new Blob([text]).stream().pipeThrough(cs); return await new Response(stream).arrayBuffer(); }

async function gunzipToText(buf) { const ds = new DecompressionStream('gzip'); const stream = new Blob([buf]).stream().pipeThrough(ds); return await new Response(stream).text(); }

async function putCompressed(id, text) {

const db = await openDB('zdb');

const tx = db.transaction('data','readwrite');

const gz = await gzipText(text);

tx.objectStore('data').put({ id, gz });

await new Promise((res, rej) => { tx.oncomplete = res; tx.onerror = () => rej(tx.error); });

db.close();

}

async function getDecompressed(id) {

const db = await openDB('zdb');

const tx = db.transaction('data','readonly');

const req = tx.objectStore('data').get(id);

const rec = await new Promise((res, rej) => { req.onsuccess = () => res(req.result); req.onerror = () => rej(req.error); });

db.close();

return rec ? gunzipToText(rec.gz) : null;

}