Node.js-based low-level loop input and process.stdin trigger end event

Inscription:

   I have been learning Node.js for the past few days, and I just learned about Node's process object and some of the content in this object. Next, today I will talk about how to use the native process to achieve, basic loop input!

text:

   First of all, we have to first understand the process object, what is the process object? The process object actually represents the application of Node.js and is also a global object. I won't go into details again. Today we mainly look at the two special attributes stdin and stdout of the process object.

•     stdin: The attribute value is an object that can be used to write to the standard input stream. By default, the standard input stream is in a paused state and needs to be used

  process.stdin.resume();

•    stdout: The property value is an object that can be used to write to the standard output stream

   Knowing the basics, we can take a look at how the code implements the loop input of the process

process.stdin.setEncoding('utf8');

process.stdin.on('readable', function(){
    var chunk = process.stdin.read(); // Get the input information
if(typeof chunk === 'string'){
    chunk = chunk.slice(0,-2); // This is to use slices to cut our carriage return\n
    process.stdout.write('stringLength:'+ chunk.length +'\n');
}
if(chunk === ''){
    process.stdin.emit('end'); // trigger end event
    return
}
if (chunk !== null) {
    process.stdout.write('data: '+ chunk +'\n');
}
});

process.stdin.on('end', function() {
    process.stdout.write('end');
});

   
    

    As you can see, when I input a string, I can get the length of my string, and output the length and string,

    And I only type carriage return when I use

slice(0,-2)

The \n is     cut out to achieve the effect of filtering carriage return.

    Among them, it is worth noting how to trigger the end event of process.stdin !

    use

    

process.stdin.exit()

    does not trigger the end event, and we can only use

process.stdin.emit('end');

    To trigger, it is worth our attention! It is also helpful for our students who want to use node to brush questions!