How to update reactivevar dependent on a framerate? - meteor

Question

I have problems understanding how exactly meteor's ReactiveVar works. What i think i should do :
Template.template_canvas.onCreated(function() {
this.config = new ReactiveVar([{
name: 'FPS',
value: Engine.mFPS
}, {
name: 'ElapsedTime',
value: Engine.mElapsedTime
}, {
name: 'LagTime',
value: Engine.mLagTime
}, {
name: 'PreviousTime',
value: Engine.mPreviousTime
}]);
});
Template.template_canvas.helpers({
displayConfigs: function() {
return Template.instance().config.get();
}
});
ALL Engine variables are updated every 40ms.
And when i try to display them :
<template name="template_canvas">
<div id='info_log' draggable="true" >
<ul>
{{#each displayConfigs}}
<li> {{name}} {{value}} </li>
{{/each}}
</ul>
</div>
<canvas id='canvas_app'></canvas>
</template>
ONLY the default variables of Engine are displayed.
Which means the variables arent changing at all.
However they are changing according to console.log !
EDIT :
export default class Engine {
static start(application) {
Engine.Application = application;
Engine.mPreviousTime = Date.now();
Engine.mLagTime = 0.0;
Engine.mIsRunning = true;
requestAnimationFrame(function() {
Engine.run.call(Engine.Application);
});
}
static run() {
if (Engine.mIsRunning) {
requestAnimationFrame(
function() {
Engine.run.call(Engine.Application);
}
);
Engine.mCurrentTime = Date.now();
Engine.mElapsedTime = Engine.mCurrentTime - Engine.mPreviousTime;
Engine.mPreviousTime = Engine.mCurrentTime;
Engine.mLagTime += Engine.mElapsedTime;
// LagTime is the sum of the elapsed Time based on the last Frame.
// So if the time passed is bigger than the given time, which bigger than milliseconds per frame
// then we have to update.
while ((Engine.mLagTime >= Engine.mMPF) && Engine.mIsRunning) {
this.update();
Engine.mLagTime -= Engine.mMPF;
}
// Should be called every 25ms, since we have 25ms per Frame.
//
this.draw();
}
}
}
// Frames per second.
//
Engine.mFPS = 40;
// Milliseconds per Frame 25ms/Frame with 40 FPS
Engine.mMPF = 1000 / Engine.mFPS;
Engine.mPreviousTime = 0;
Engine.mLagTime = 0;
Engine.mCurrentTime = 0;
Engine.mElapsedTime = 0;
Engine.mIsRunning = false;
Engine.Application = null;