diff --git a/src/curve.ts b/src/classic-curve.ts
similarity index 81%
rename from src/curve.ts
rename to src/classic-curve.ts
index 6115e36..ee5ee69 100644
--- a/src/curve.ts
+++ b/src/classic-curve.ts
@@ -1,12 +1,12 @@
-import SiriWave, { ICurveDefinition, ICurve } from "./index";
-export class Curve implements ICurve {
+import SiriWave, { IClassicCurveDefinition, ICurve } from "./index";
+export class ClassicCurve implements ICurve {
   ctrl: SiriWave;
-  definition: ICurveDefinition;
+  definition: IClassicCurveDefinition;
   ATT_FACTOR = 4;
   GRAPH_X = 2;
   AMPLITUDE_FACTOR = 0.6;
 
-  constructor(ctrl: SiriWave, definition: ICurveDefinition) {
+  constructor(ctrl: SiriWave, definition: IClassicCurveDefinition) {
     this.ctrl = ctrl;
     this.definition = definition;
   }
@@ -25,7 +25,7 @@ export class Curve implements ICurve {
       (this.globalAttFn(i) *
         (this.ctrl.heightMax * this.ctrl.amplitude) *
         (1 / this.definition.attenuation) *
-        Math.sin(this.ctrl.opt.frequency * i - this.ctrl.phase))
+        Math.sin(this.ctrl.opt.frequency! * i - this.ctrl.phase))
     );
   }
 
@@ -40,14 +40,14 @@ export class Curve implements ICurve {
     ctx.lineWidth = this.definition.lineWidth;
 
     // Cycle the graph from -X to +X every PX_DEPTH and draw the line
-    for (let i = -this.GRAPH_X; i <= this.GRAPH_X; i += this.ctrl.opt.pixelDepth) {
+    for (let i = -this.GRAPH_X; i <= this.GRAPH_X; i += this.ctrl.opt.pixelDepth!) {
       ctx.lineTo(this._xpos(i), this.ctrl.heightMax + this._ypos(i));
     }
 
     ctx.stroke();
   }
 
-  static getDefinition(): ICurveDefinition[] {
+  static getDefinition(): IClassicCurveDefinition[] {
     return [
       {
         attenuation: -2,
diff --git a/src/index.ts b/src/index.ts
index 9eab7d9..8701796 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,5 +1,5 @@
-import { Curve } from "./curve";
-import { iOS9Curve } from "./ios9curve";
+import { ClassicCurve } from "./classic-curve";
+import { iOS9Curve } from "./ios9-curve";
 
 enum CurveStyle {
   "ios" = "ios",
@@ -37,14 +37,19 @@ export type Options = {
   curveDefinition?: ICurveDefinition[];
 };
 
-export type ICurveDefinition = {
-  attenuation?: number;
-  lineWidth?: number;
-  opacity?: number;
+export type IiOS9CurveDefinition = {
   supportLine?: boolean;
-  color?: string;
+  color: string;
+};
+
+export type IClassicCurveDefinition = {
+  attenuation: number;
+  lineWidth: number;
+  opacity: number;
 };
 
+export type ICurveDefinition = IiOS9CurveDefinition | IClassicCurveDefinition;
+
 export interface ICurve {
   draw: () => void;
 }
@@ -66,15 +71,15 @@ export default class SiriWave {
   heightMax: number;
   color: string;
   interpolation: {
-    speed: number;
-    amplitude: number;
+    speed: number | null;
+    amplitude: number | null;
   };
 
   canvas: HTMLCanvasElement;
   ctx: CanvasRenderingContext2D;
 
-  animationFrameId: number;
-  timeoutId: ReturnType<typeof setTimeout>;
+  animationFrameId: number | undefined;
+  timeoutId: ReturnType<typeof setTimeout> | undefined;
 
   constructor({ container, ...rest }: Options) {
     const csStyle = window.getComputedStyle(container);
@@ -109,12 +114,12 @@ export default class SiriWave {
     /**
      * Width of the canvas multiplied by pixel ratio
      */
-    this.width = Number(this.opt.ratio * this.opt.width);
+    this.width = Number(this.opt.ratio! * this.opt.width!);
 
     /**
      * Height of the canvas multiplied by pixel ratio
      */
-    this.height = Number(this.opt.ratio * this.opt.height);
+    this.height = Number(this.opt.ratio! * this.opt.height!);
 
     /**
      * Maximum height for a single wave
@@ -124,7 +129,7 @@ export default class SiriWave {
     /**
      * Color of the wave (used in Classic iOS)
      */
-    this.color = `rgb(${this.hex2rgb(this.opt.color)})`;
+    this.color = `rgb(${this.hex2rgb(this.opt.color!)})`;
 
     /**
      * An object containing controller variables that need to be interpolated
@@ -143,7 +148,11 @@ export default class SiriWave {
     /**
      * 2D Context from Canvas
      */
-    this.ctx = this.canvas.getContext("2d");
+    const ctx = this.canvas.getContext("2d");
+    if (ctx === null) {
+      throw new Error("Unable to create 2D Context");
+    }
+    this.ctx = ctx;
 
     // Set dimensions
     this.canvas.width = this.width;
@@ -153,19 +162,23 @@ export default class SiriWave {
     if (this.opt.cover === true) {
       this.canvas.style.width = this.canvas.style.height = "100%";
     } else {
-      this.canvas.style.width = `${this.width / this.opt.ratio}px`;
-      this.canvas.style.height = `${this.height / this.opt.ratio}px`;
+      this.canvas.style.width = `${this.width / this.opt.ratio!}px`;
+      this.canvas.style.height = `${this.height / this.opt.ratio!}px`;
     }
 
     // Instantiate all curves based on the style
     switch (this.opt.style) {
       case CurveStyle.ios9:
-        this.curves = (this.opt.curveDefinition || iOS9Curve.getDefinition()).map((def) => new iOS9Curve(this, def));
+        this.curves = ((this.opt.curveDefinition || iOS9Curve.getDefinition()) as IiOS9CurveDefinition[]).map(
+          (def) => new iOS9Curve(this, def),
+        );
         break;
 
       case CurveStyle.ios:
       default:
-        this.curves = (this.opt.curveDefinition || Curve.getDefinition()).map((def) => new Curve(this, def));
+        this.curves = ((this.opt.curveDefinition || ClassicCurve.getDefinition()) as IClassicCurveDefinition[]).map(
+          (def) => new ClassicCurve(this, def),
+        );
         break;
     }
 
@@ -200,10 +213,13 @@ export default class SiriWave {
   /**
    * Interpolate a property to the value found in this.interpolation
    */
-  lerp(propertyStr: "amplitude" | "speed"): number {
-    this[propertyStr] = this.intLerp(this[propertyStr], this.interpolation[propertyStr], this.opt.lerpSpeed);
-    if (this[propertyStr] - this.interpolation[propertyStr] === 0) {
-      this.interpolation[propertyStr] = null;
+  lerp(propertyStr: "amplitude" | "speed"): number | null {
+    const prop = this.interpolation[propertyStr];
+    if (prop !== null) {
+      this[propertyStr] = this.intLerp(this[propertyStr], prop, this.opt.lerpSpeed!);
+      if (this[propertyStr] - prop === 0) {
+        this.interpolation[propertyStr] = null;
+      }
     }
     return this[propertyStr];
   }
@@ -232,8 +248,8 @@ export default class SiriWave {
     this._clear();
 
     // Interpolate values
-    if (this.interpolation.amplitude !== null) this.lerp("amplitude");
-    if (this.interpolation.speed !== null) this.lerp("speed");
+    this.lerp("amplitude");
+    this.lerp("speed");
 
     this._draw();
     this.phase = (this.phase + (Math.PI / 2) * this.speed) % (2 * Math.PI);
diff --git a/src/ios9curve.ts b/src/ios9-curve.ts
similarity index 88%
rename from src/ios9curve.ts
rename to src/ios9-curve.ts
index 03c93f0..6b5f7a6 100644
--- a/src/ios9curve.ts
+++ b/src/ios9-curve.ts
@@ -1,8 +1,8 @@
-import SiriWave, { ICurveDefinition, ICurve } from "./index";
+import SiriWave, { ICurve, IiOS9CurveDefinition } from "./index";
 
 export class iOS9Curve implements ICurve {
   ctrl: SiriWave;
-  definition: ICurveDefinition;
+  definition: IiOS9CurveDefinition;
 
   spawnAt: number;
   noOfCurves: number;
@@ -32,10 +32,23 @@ export class iOS9Curve implements ICurve {
   SPEED_RANGES: [number, number] = [0.5, 1];
   DESPAWN_TIMEOUT_RANGES: [number, number] = [500, 2000];
 
-  constructor(ctrl: SiriWave, definition: ICurveDefinition) {
+  constructor(ctrl: SiriWave, definition: IiOS9CurveDefinition) {
     this.ctrl = ctrl;
     this.definition = definition;
 
+    this.noOfCurves = 0;
+    this.spawnAt = 0;
+    this.prevMaxY = 0;
+
+    this.phases = [];
+    this.offsets = [];
+    this.speeds = [];
+    this.finalAmplitudes = [];
+    this.widths = [];
+    this.amplitudes = [];
+    this.despawnTimeouts = [];
+    this.verses = [];
+
     this.respawn();
   }
 
@@ -98,9 +111,9 @@ export class iOS9Curve implements ICurve {
       // Generate a static T so that each curve is distant from each oterh
       let t = 4 * (-1 + (ci / (this.noOfCurves - 1)) * 2);
       // but add a dynamic offset
-      t += this.offsets[ci];
+      t += this.offsets![ci];
 
-      const k = 1 / this.widths[ci];
+      const k = 1 / this.widths![ci];
       const x = i * k - t;
 
       y += Math.abs(this.amplitudes[ci] * this.sin(this.verses[ci] * x, this.phases[ci]) * this.globalAttFn(x));
@@ -127,7 +140,7 @@ export class iOS9Curve implements ICurve {
   drawSupportLine() {
     const { ctx } = this.ctrl;
 
-    const coo = [0, this.ctrl.heightMax, this.ctrl.width, 1];
+    const coo: [number, number, number, number] = [0, this.ctrl.heightMax, this.ctrl.width, 1];
     const gradient = ctx.createLinearGradient.apply(ctx, coo);
     gradient.addColorStop(0, "transparent");
     gradient.addColorStop(0.1, "rgba(255,255,255,.5)");
@@ -167,7 +180,7 @@ export class iOS9Curve implements ICurve {
     for (const sign of [1, -1]) {
       ctx.beginPath();
 
-      for (let i = -this.GRAPH_X; i <= this.GRAPH_X; i += this.ctrl.opt.pixelDepth) {
+      for (let i = -this.GRAPH_X; i <= this.GRAPH_X; i += this.ctrl.opt.pixelDepth!) {
         const x = this._xpos(i);
         const y = this._ypos(i);
         ctx.lineTo(x, this.ctrl.heightMax - sign * y);
@@ -192,7 +205,7 @@ export class iOS9Curve implements ICurve {
     return null;
   }
 
-  static getDefinition(): ICurveDefinition[] {
+  static getDefinition(): IiOS9CurveDefinition[] {
     return [
       {
         color: "255,255,255",
diff --git a/tsconfig.json b/tsconfig.json
index 4e380db..d07d102 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -2,7 +2,8 @@
   "compilerOptions": {
     "noImplicitAny": true,
     "module": "es6",
-    "target": "es5"
+    "target": "es5",
+    "strict": true
   },
   "include": ["./src/**/*"],
   "exclude": ["./node_modules"]