react-native-mock-tmp-build/build/api/Animated/SpringConfig.js

A fully mocked and test-friendly version of react native

/**
 * https://github.com/facebook/react-native/blob/master/Libraries/Animated/src/SpringConfig.js
 */

function tensionFromOrigamiValue(oValue){
return(oValue-30)*3.62+194;
}

function frictionFromOrigamiValue(oValue){
return(oValue-8)*3+25;
}

function fromOrigamiTensionAndFriction(tension,friction){
return{
tension:tensionFromOrigamiValue(tension),
friction:frictionFromOrigamiValue(friction)};

}

function fromBouncinessAndSpeed(bounciness,speed){
function normalize(value,startValue,endValue){
return(value-startValue)/(endValue-startValue);
}

function projectNormal(n,start,end){
return start+n*(end-start);
}

function linearInterpolation(t,start,end){
return t*end+(1-t)*start;
}

function quadraticOutInterpolation(t,start,end){
return linearInterpolation(2*t-t*t,start,end);
}

function b3Friction1(x){
return 0.0007*Math.pow(x,3)-
0.031*Math.pow(x,2)+0.64*x+1.28;
}

function b3Friction2(x){
return 0.000044*Math.pow(x,3)-
0.006*Math.pow(x,2)+0.36*x+2;
}

function b3Friction3(x){
return 0.00000045*Math.pow(x,3)-
0.000332*Math.pow(x,2)+0.1078*x+5.84;
}

function b3Nobounce(tension){
if(tension<=18){
return b3Friction1(tension);
}else if(tension>18&&tension<=44){
return b3Friction2(tension);
}
return b3Friction3(tension);
}

var b=normalize(bounciness/1.7,0,20);
b=projectNormal(b,0,0.8);
var s=normalize(speed/1.7,0,20);
var bouncyTension=projectNormal(s,0.5,200);
var bouncyFriction=quadraticOutInterpolation(
b,
b3Nobounce(bouncyTension),
0.01);


return{
tension:tensionFromOrigamiValue(bouncyTension),
friction:frictionFromOrigamiValue(bouncyFriction)};

}

module.exports={
fromOrigamiTensionAndFriction:fromOrigamiTensionAndFriction,
fromBouncinessAndSpeed:fromBouncinessAndSpeed};