TextEncoderStream 与 TextDecoderStream 文本管道转换与持久化实践

概述编码与解码流简化了文本与二进制之间的转换。本文给出管道化转换与持久化示例。能力检测与管道const supportsTES = typeof TextEncoderStream === 'function';

const supportsTDS = typeof TextDecoderStream === 'function';

function toUpper() {

return new TransformStream({

transform(chunk, controller) {

controller.enqueue(chunk.toUpperCase());

}

});

}

async function processText(text) {

if (!(supportsTES && supportsTDS)) return text.toUpperCase();

const rs = new Blob([text]).stream().pipeThrough(new TextDecoderStream()).pipeThrough(toUpper()).pipeThrough(new TextEncoderStream());

return await new Response(rs).text();

}

增量持久化function openDB(name) { return new Promise((resolve, reject) => { const r = indexedDB.open(name, 1); r.onupgradeneeded = () => { const db = r.result; if (!db.objectStoreNames.contains('texts')) db.createObjectStore('texts', { autoIncrement: true }); }; r.onsuccess = () => resolve(r.result); r.onerror = () => reject(r.error); }); }

async function saveProcessed(text) {

const db = await openDB('textdb');

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

tx.objectStore('texts').add({ value: text, ts: Date.now() });

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

db.close();

}