My node.js application has a lot of console logs, which are important for me to see (it's quite a big app so runs for a long time and I need to know that things are still progressing) but I'm ending up with thousands of lines of console logs.
Is it somehow possible to do a console.update that erases/replaces a console line rather than creating a new line?
Sure, you can do this using a module I helped create: fknsrs/jetty
Install via
npm install jetty
Here's a usage example
// Yeah, Jetty!
var Jetty = require("jetty");
// Create a new Jetty object. This is a through stream with some additional
// methods on it. Additionally, connect it to process.stdout
var jetty = new Jetty(process.stdout);
// Clear the screen
jetty.clear();
// write something
jetty.text("hello world");
jetty.moveTo([0,0]);
jetty.text("hello panda");
Jetty is not super useful when used on it's own. It is much more effective when you build some abstraction on top of it to make your jetty calls less verbose.
Check out how I use jetty in fknsrs/bento for more usage examples.
To write a partial line.
process.stdout.write("text");
process.stdout.write("more");
process.stdout.write("\n"); // end the line
If the volume of output is the real issue then you'll probably to rethink your logging. You could use a logging system that allows selective runtime logging to narrow your output to what you need.
// The sections we want to log and the minimum level
var LOG_LEVEL = 4;
var LOG_SECTIONS = ["section1","section2","section3"];
function logit(msg, section, level) {
if (LOG_SECTIONS.indexOf(section) > -1 && LOG_LEVEL >= level) {
console.log(section + ":" + msg);
}
}
logit("message 1", "section1", 4); // will log
logit("message 2", "section2", 4); // will log
logit("message 3", "section3", 2); // wont log, below log level
logit("message 4", "section4", 4); // wont log, not in a log section