improve error handling

TypeScript/src/decode.ts

@@ -1,5 +1,6 @@
 import { decode83 } from "./base83";
 import { sRGBToLinear, signPow, linearTosRGB } from "./utils";
+import { ValidationError } from "./error";
 
 const decodeDC = (value: number) => {
   const intR = value >> 16;
@@ -31,8 +32,9 @@ const decode = (
   punch = punch | 1;
 
   if (blurhash.length < 6) {
-    console.error("too short blurhash");
-    return null;
+    throw new ValidationError(
+      "The blurhash string must be at least 6 characters"
+    );
   }
 
   const sizeFlag = decode83(blurhash[0]);
@@ -43,11 +45,12 @@ const decode = (
   const maximumValue = (quantisedMaximumValue + 1) / 166;
 
   if (blurhash.length !== 4 + 2 * numX * numY) {
-    console.error(
-      "blurhash length mismatch",
-      blurhash.length,
-      4 + 2 * numX * numY
+    throw new ValidationError(
+      `blurhash length mismatch: length is ${
+        blurhash.length
+      } but it should be ${4 + 2 * numX * numY}`
     );
+
     return null;
   }
 

TypeScript/src/encode.ts

@@ -1,5 +1,6 @@
 import { encode83 } from "./base83";
 import { sRGBToLinear, signPow, linearTosRGB } from "./utils";
+import { ValidationError } from "./error";
 
 type NumberTriplet = [number, number, number];
 
@@ -71,10 +72,10 @@ const encode = (
   componentY: number
 ): string => {
   if (componentX < 1 || componentX > 9 || componentY < 1 || componentY > 9) {
-    throw new Error("BlurHash must have between 1 and 9 components");
+    throw new ValidationError("BlurHash must have between 1 and 9 components");
   }
   if (width * height * 4 !== pixels.length) {
-    throw new Error("Width and height must match the pixels array");
+    throw new ValidationError("Width and height must match the pixels array");
   }
 
   let factors: Array<[number, number, number]> = [];

TypeScript/src/error.ts

@@ -0,0 +1,7 @@
+export class ValidationError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = "ValidationError";
+    this.message = message;
+  }
+}

TypeScript/src/index.ts

@@ -1,2 +1,3 @@
 export { default as decode } from "./decode";
 export { default as encode } from "./encode";
+export * from "./error";