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法学Node.js 中 Stream writable.writableLength 属性
writable.writableLength 属性用于显示排队中准备写入的字节或对象数。这用于根据 highWaterMark 的状态检查数据。
语法
writeable.writableLength
示例 1
创建一个名为 writableLength.js 的文件并复制下面的代码段。创建文件后，使用以下命令运行此代码，如下例所示 −
node writableLength.js
// Program to demonstrate writable.writableLength method
const stream = require('stream');
// Creating a data stream with writable
const writable = new stream.Writable({
// Writing the data from stream
write: function(chunk, encoding, next) {
// Converting the data chunk to be displayed
console.log(chunk.toString());
next();
}
});
// Writing data - Not in the buffer queue
writable.write('Hi - This data will not be counted');
// Calling the cork() function
writable.cork();
// Again writing some data
writable.write('Welcome to TutorialsPoint !');
writable.write('SIMPLY LEARNING ');
writable.write('This data will be corked in the memory');
// Printing the length of the queue data
console.log(writable.writableLength);输出
C:\home
ode>> node writableLength.js Hi - This data will not be counted 81
将堵塞在缓冲队列中的数据进行计数并打印到控制台。
示例
我们再看一个示例。
// Program to demonstrate writable.cork() method
const stream = require('stream');
// Creating a data stream with writable
const writable = new stream.Writable({
// Writing the data from stream
write: function(chunk, encoding, next) {
// Converting the data chunk to be displayed
console.log(chunk.toString());
next();
}
});
// Writing data - Not in the buffer queue
writable.write('Hi - This data will not be counted');
// Calling the cork() function
writable.cork();
// Again writing some data
writable.write('Welcome to TutorialsPoint !');
writable.write('SIMPLY LEARNING ');
writable.write('This data will be corked in the memory');
// Printing the length of the queue data
console.log(writable.writableLength);
// Flushing the data from buffered memory
writable.uncork()
console.log(writable.writableLength);输出
C:\home
ode>> node writableLength.js Hi - This data will not be counted 81 Welcome to TutorialsPoint ! SIMPLY LEARNING This data will be corked in the memory 0
由于 uncork() 之后数据已经刷新。该队列将不会保存任何数据，这就是返回的长度为 0 的原因。
更新于： 2021-05-20
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