Node.js Stream 可写.可写成品属性
原文:https://www . geesforgeks . org/node-js-stream-writteable-finished-property/
在“完成”事件发出之前，立即将可写.可写已完成属性设置为真。
语法:
writable.writableFinished
返回值:如果在调用“完成”事件之前调用该事件，则返回真，否则返回假。 以下示例说明了在 Node.js 中使用可写可写成品属性:
例 1:
// Node.js program to demonstrate the
// writable.writableFinished Property
// Accessing stream module
const stream = require('stream');
// Creating a stream and creating
// a write function
const writable = new stream.Writable({
// Write function with its
// parameters
write: function(chunk, encoding, next) {
// Converting the chunk of
// data to string
console.log(chunk.toString());
next();
}
});
// Using for loop and calling
// write method
for (let i = 0; i < 5; i++) {
writable.write(`GfG, #${i}!`);
}
// Emitting finish event
writable.on('finish', () => {
console.log('All writes are now complete.');
});
// Calling end function
writable.end('This is the end\n');
// Calling writable.writableFinished
// Property
writable.writableFinished;
writable.destroy();
输出:
GfG, #0!
GfG, #1!
GfG, #2!
GfG, #3!
GfG, #4!
This is the end
All writes are now complete.
例 2:
// Node.js program to demonstrate the
// writable.writableFinished Property
// Accessing stream module
const stream = require('stream');
// Creating a stream and creating
// a write function
const writable = new stream.Writable({
// Write function with its
// parameters
write: function(chunk, encoding, next) {
// Converting the chunk of
// data to string
console.log(chunk.toString());
next();
}
});
// Calling write() method
writable.write('GfG');
// Calling writable.writableFinished
// Property
writable.writableFinished;
writable.destroy();
输出
GfG
在上面的例子中，输出为假，因为在可写.可写已完成属性之前没有调用“完成”事件。
参考:T2。
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