Spark AR Why if-else if construction doesn't work?

Question

I don't understand why if-else construction doesn't work.

const Diagnostics = require('Diagnostics');
const Reactive = require('Reactive');


var num = 5;
var firstCondition= false;
var secondCondition = false;

function func(){
    firstCondition = Reactive.ge(num, 10);
    secondCondition = Reactive.lt(num, 10);
    if(firstCondition){             //false
      num = 0;
    } else if(secondCondition){     //true
      num = 1;
    }
}
func();

Diagnostics.watch("num - ", num);
Diagnostics.watch("firstCondition ", firstCondition);
Diagnostics.watch("secondCondition ", secondCondition);

num shows 0:( What am I doing wrong? Is it specific of reactive programming?

score 2 · Accepted Answer · answered Dec 12 '19 at 08:50

There are two issues in your example:

signals can be confusing and return true just because the variable is there, so you need to check: if (firstCondition.pinLastValue()) to get the value of the boolean signal.

secondly, I guess your function is not updated, you need something like this:

const Time = require('Time'); const interval = Time.setInterval(func(), 500);

score 1 · Answer 2 · answered Dec 20 '19 at 14:58

1

You need to use different mindset here:

const conditionedSignal = inputSignal.ge(10).ifThenElse(0, 1);

This is a scalarSignal class, not a JS Number!

answered Dec 20 '19 at 14:58

lisichka ggg

563
3
15

score 0 · Answer 3 · answered Dec 17 '19 at 19:44

Spark AR Studio uses reactive programming, a declarative programming model that uses asynchronous data streams. This guide will cover the benefits and use of reactive programming within Spark AR Studio.

https://sparkar.facebook.com/ar-studio/learn/documentation/scripting/reactive/

Spark AR Why if-else if construction doesn't work?

3 Answers3