Justin Bernegger

I've tried running the sample code from this page: https://docs.cycling74.com/max8/vignettes/jsliveapi in a new device while trying to learn max for live js objects.

When I compile the code I get several errors, first being that 'return' is being called from outside of a function... which is accurate.

When I remove the return I'm told the 'api' object is never created.

I have simply copy and pasted the sample code from the tutorial. Is there something I'm missing? Or is this code untested/out of date?

I've tried running the sample code from this page: https://docs.cycling74.com/max8/vignettes/jsliveapi in a new device while trying to ... 

liveapi-js-sample-not-working

I can reproduce your error on my end too, however, I was able to get the api object to be created. Can you make sure that you are running the js within a Max for Live context, and not just Max?

// Create a sample callback function
function sample_callback(args) {
  post("callback called with arguments:", args, "\n")
}  

// Create a new LiveAPI object, passing the callback and an API path
var api = new LiveAPI(sample_callback, "live_set tracks 0")

// A function for posting some API information extracted via the javascript live API
function postApiInformation() {
  post("api.mode", api.mode ? "follows path" : "follows object", "\n")
  post("api.id is", api.id, "\n")
  post("api.path is", api.path, "\n")
  post("api.children are", api.children, "\n")
  post('api.getcount("devices")', api.getcount("devices"), "\n")
  
  api.property = "mute"
  post("api.property is", api.property, "\n")
  post("type of", api.property, "is", api.proptype, "\n")
}

// Checks if the API loaded and then calls postApiInformation() if it did.
function checkApiExists() {
  // Check that the API was loaded
  if (api) { // If it loaded properly
    post("API loaded\n")
    postApiInformation()
  } else { // If the api object is not valid
    post("API did not load, no API object\n")
  }
}

// Call checkApiExists function to start
checkApiExists()

The LiveAPI object can’t be assigned in the global context. Someone probably took that code from inside a function (like function bang()), and that’s why the “return” statement was there.

EDIT: Though I'm surprised to say James' code actually ran for me, but perhaps its because I pasted it into a device that was already valid and the LiveAPI was already accessible. The normal issue I would expect is that when your device loads, the global section of the JS code tries to assign the LiveAPI object before, in the Max context, the [live.thisdevice] has signaled that the LiveAPI is initialized and ready to use.

See the "Technical Note" below the description of the LiveAPI Constructor.

The LiveAPI object can’t be assigned in the global context.  Someone probably took that code from inside a function (like function bang()), and that’s why the “return” statement was there.

EDIT: Though I'm surprised to say James' code actually ran for me, but perhaps its because I pasted it into a device that was already valid and the LiveAPI was already accessible.  The normal issue I would expect is that when your device loads, the global section of the JS code tries to assign the LiveAPI object before, in the Max context, the [live.thisdevice] has signaled that the LiveAPI is initialized and ready to use.

I don't know enough about the internal implementation and upon re-reading that documentation I am unsure why the code also works, though it does. Your hunch seems correct to me, that this code used to run inside a function.

If one feels truly unsafe by my code you could just put the Live API object creation inside a function and pass it around as an argument to other functions:

// Create a sample callback function
function sample_callback(args) {
  post("callback called with arguments:", args, "\n")
}  

// A function for posting some API information extracted via the javascript live API
function postApiInformation(api) {
  post("api.mode", api.mode ? "follows path" : "follows object", "\n")
  post("api.id is", api.id, "\n")
  post("api.path is", api.path, "\n")
  post("api.children are", api.children, "\n")
  post('api.getcount("devices")', api.getcount("devices"), "\n")
  
  api.property = "mute"
  post("api.property is", api.property, "\n")
  post("type of", api.property, "is", api.proptype, "\n")
}

// Checks if the API loaded and then calls postApiInformation() if it did.
function checkApiExists() {
  // Create a new LiveAPI object, passing the callback and an API path
  var api = new LiveAPI(sample_callback, "live_set tracks 0")
  // Check that the API was loaded
  if (api) { // If it loaded properly
    post("API loaded\n")
    postApiInformation(api)
  } else { // If the api object is not valid
    post("API did not load, no API object\n")
  }
}

// Call checkApiExists function to start
checkApiExists()

LiveAPI JS Sample not working