Stamp-Stream

A through stream that stamps all incoming lines of data with a message and emits it back out

npm install stamp-stream

Usage

Usage is simple

var stamp = require('stamp-stream');
var stream = stamp('hello ');
 
stream.pipe(process.stdout); // "hello world\n" is printed
 
stream.write('wor');
stream.write('ld\n');

You can make dynamic stamps as well by passing in a function instead

var lines = 0;
var stream = stamp(function() {
    return (lines++)+' '; // prefix with line number
});
 
stream.pipe(process.stdout); // "0 first\n1 second\n2 third\n" is printed
 
stream.write('first\n');
stream.write('seco')
stream.write('nd\nthird\n');

Stamp-Stream can be useful to stamp output from an application with timestamp or similar. Assume we have a file called stamp.js

var stamp = require('stamp-stream');
 
process.stdin
    .pipe(stamp(function() {
        return new Date().toGMTString()+' ';
    }))
    .pipe(process.stdout);
 
process.stdin.resume();

If we now call node my-app.js | node stream.js all log messages from my-app.js would be prefixed by a timestamp.

License

MIT