Out of control trains!

src/utils.ts

@@ -5,10 +5,26 @@ export const randomInt = (min: number, max: number): number => (
   Math.floor(Math.random() * (max - (min + 1))) + min
 );
 
+export const weightedRandom = (choices: any[], weights: number[]): any => {
+  const totalWeight = weights.reduce((a, b) => a + b, 0);
+  const rand = randomInt(0, totalWeight);
+  let cumulWeight = 0;
+  for (let i = 0; i < weights.length; i += 1) {
+    cumulWeight += weights[i];
+    if (rand < cumulWeight) {
+      return choices[i];
+    }
+  }
+};
+
 export const randomPoint = () => (
   new PIXI.Point(randomInt(0, window.innerWidth), randomInt(0, window.innerHeight))
 );
 
+export const pointsEqual = (pointA: PIXI.Point, pointB: PIXI.Point): boolean => (
+  (pointA.x === pointB.x && pointA.y === pointB.y)
+);
+
 export const distance = (pointA: PIXI.Point, pointB: PIXI.Point): number => {
   const distX = pointA.x - pointB.x;
   const distY = pointA.y - pointB.y;