File System Access 快速权限检测与用户交互提示实践

概述权限提示应在用户发起的交互中进行。本文提供检测与提示封装。检测与提示async function ensureRW(handle) { if (typeof handle.queryPermission === 'function') { const s = await handle.queryPermission({ mode: 'readwrite' }); if (s === 'granted') return true; } if (typeof handle.requestPermission === 'function') { const s2 = await handle.requestPermission({ mode: 'readwrite' }); return s2 === 'granted'; } return true; } async function onClickSave(fn) { const handle = await window.showSaveFilePicker({ suggestedName: 'data.txt' }); const ok = await ensureRW(handle); if (!ok) { alert('请授权写入权限'); return; } const ws = await handle.createWritable(); await ws.write(new Blob([await fn()], { type: 'text/plain' })); await ws.close(); }