Peter Nyboer

It seems like there's some fairly gnarly string operations going on in the JS LiveAPI paths.

Let's say I want to get a path from something, and prepare a path, based on what I find...

function test(){
var api = new LiveAPI();
api.path = 'this_device'; //returns sth like "live_set tracks 0 devices 0"
}

What I'm interested in is the device to the right of this_device. How can I unravel that result and change that 0, then add a few more things to the path, for example:

I've tried various tricks of unravelling the string and packing it together into something that I can use to set to api.path, but I keep getting errors.

It seems like there's some fairly gnarly string operations going on in the JS LiveAPI paths.
Let's say I want to get a path from something, and prepare a path, based on what I find...

If api.path is"live_set tracks 0 devices 0"
What I'm interested in is the device to the right of this_device. How can I unravel that result and change that 0, then add a few more things to the path, for example:"live_set tracks 0 devices 1 chains 0"
??
I've tried various tricks of unravelling the string and packing it together into something that I can use to set to api.path, but I keep getting errors.
Any hints?
Peter


manipulating-paths-in-js-liveapi

I don't know how efficient this is compared to good old fashioned string manipulation, but I've always found arrays to be more intuitive.

var oldString = "live_set tracks 0 devices 0";
var strArray = oldString.split(" ");

So now it's a list of words (as previously separated by spaces).

being array members now, we can alter the parameters individually. The "0" we want to change was the 6th list item, but we're counting up from 0, so it's #5...

Then, when we're done, turn the array back into a string.

(each element is separated by a spacebar.

And then, appending strings is just the plus sign.

var oldString = "live_set tracks 0 devices 0";
var strArray = oldString.split(" ");
strArray[5] = "1";
var newString = strArray.join(" ") + " chains 0";

"because you're trying to perform math operations on a string."

"30" + 1 does not equal 31. It equals "301". That's probably out of range, so your code's going to behave unpredictably.

You can't increment a string like this. That's an error.

var fakeNumber = "30";
fakeNumber = Number(fakeNumber) + 1;

being array members now, we can alter the parameters individually.  The "0" we want to change was the 6th list item, but we're counting up from 0, so it's #5...

The real question is "why am I getting errors?" and the answer is "because you're trying to perform math operations on a string."

"30" + 1 does not equal 31.  It equals "301".  That's probably out of range, so your code's going to behave unpredictably.

You can't increment a string like this.  That's an error.

Actually, it looks like api.path also has quotation marks baked in. That'll get in your way.

So, something like this might be less fragile:

I'm not sure how to actually pipe that new path back into the api and make it useful to you, but there it is.

(worth pointing out: I've got no experience coding for the Live API, and every part of this is probably wrong. we learn by doing...)

Actually, it looks like api.path also has quotation marks baked in.  That'll get in your way.

(worth pointing out: I've got no experience coding for the Live API, and every part of this is probably wrong.  we learn by doing...)


Okay, that last part was easily researched. This may not be at all efficient, but it should at least be usable. I think.

(Doesn't look like the quotation marks are actually needed, so we're not adding them back anymore. And my "removeQuotes" function was embarrassingly bad, so I rewrote that as well.)

Okay, that last part was easily researched.  This may not be at all efficient, but it should at least be usable.  I think.

(Doesn't look like the quotation marks are actually needed, so we're not adding them back anymore.  And my "removeQuotes" function was embarrassingly bad, so I rewrote that as well.)

Thank you for your awesome code!! Here's a very slightly modified version that just gives you the next device path.

FWIW there is an ‘unquotedpath’ property on live objects that obviates the “removeQuotes” function. (Though I wonder if that wasn’t true when this thread was initially written up 8 years ago...)

FWIW there is an ‘unquotedpath’ property on live objects that obviates the “removeQuotes” function.  (Though I wonder if that wasn’t true when this thread was initially written up 8 years ago...)

Manipulating paths in JS LiveAPI.