Question

I’m working on making a script with node.js for setting up my dzen2 in i3, and haven’t really used node for anything like this before.

I need the geometry of the screen to start with, which I can get with something like this:

geometry = getGeo();

function getGeo() {
  var sh = require('child_process').exec("i3-msg -t get_outputs",
    function(error, stdout, stderr) {
      var out = JSON.parse(stdout);
      return out[0].rect; //this is the geometry, {"x":0, "y":0, "width":1280, "height":768}
  });
};

console.log(geometry);

console.log is logging undefined.

I’m not sure what the proper way to do this is, my brain is tired.

Answer 1

You can’t return from the callback function since is async.
Rather write another function and pass the callback object to it.

function getGeo() {
var sh = require('child_process').exec("i3-msg -t get_outputs",
    function(error, stdout, stderr) {
      var out = JSON.parse(stdout);
      getRect(return out[0].rect);
    });
};

function getRect(rect) {
    // Utilize rect here...
}