WritableStreamDefaultWriter.ready
Baseline Widely available
This feature is well established and works across many devices and browser versions. It’s been available across browsers since June 2022.
WritableStreamDefaultWriter 接口的只读属性 ready 返回一个 Promise，当流填充内部队列的所需大小从非正数变为正数时兑现，表明它不再应用背压。
值
一个 Promise。
示例
以下示例使用了 ready 属性的两种用法。第一种使用 ready 来确保 WritableStream 已完成写入，因此能够保证其已经准备好接收新的数据。第二种也检查 WritableStream 是否完成写入，但是这一次是因为写入操作必须在 writer 关闭之前完成。
js
function sendMessage(message, writableStream) {
// defaultWriter is of type WritableStreamDefaultWriter
var defaultWriter = writableStream.getWriter();
var encoder = new TextEncoder();
var encoded = encoder.encode(message, { stream: true });
encoded.forEach(function (chunk) {
// Make sure the stream and its writer are able to
// receive data.
defaultWriter.ready.then(function () {
defaultWriter
.write(chunk)
.then(function () {
console.log("Chunk written to sink.");
})
.catch(function (err) {
console.log("Chunk error: " + err);
});
});
// Call ready again to ensure that all chunks are written
// before closing the writer.
defaultWriter.ready.then(function () {
defaultWriter
.close()
.then(function () {
console.log("All chunks written");
})
.catch(function (err) {
console.log("Stream error: " + err);
});
});
});
}
规范
| Specification |
|---|
| Streams # ref-for-default-writer-ready⑨ |