Fix some issues

frontend/src/scripts/helper/linear-extrapolator.ts

@@ -0,0 +1,38 @@
+import { clamp } from 'shared';
+
+export class LinearExtrapolator {
+  private velocity = 0;
+  private compensationVelocity = 0;
+  private timeSinceSet = 0;
+
+  constructor(private currentValue: number) {}
+
+  public addFrame(value: number, rateOfChange: number) {
+    this.timeSinceSet = 0;
+    const differenceFromCurrent = value - this.currentValue;
+
+    if (Math.abs(differenceFromCurrent) > 200) {
+      this.currentValue = value;
+      this.compensationVelocity = 0;
+    } else {
+      this.compensationVelocity = differenceFromCurrent / (1 / 30);
+    }
+
+    this.velocity = rateOfChange;
+  }
+
+  public getValue(deltaTime: number): number {
+    this.currentValue += deltaTime * this.velocity;
+
+    const compensationTimeLeft = 1 / 30 - this.timeSinceSet;
+
+    if (compensationTimeLeft > 0) {
+      this.currentValue +=
+        Math.min(compensationTimeLeft, deltaTime) * this.compensationVelocity;
+    }
+
+    this.timeSinceSet += deltaTime;
+
+    return this.currentValue;
+  }
+}