refactor: implement error handles for common methods

Refs: #25

src/errors.ts

@@ -62,3 +62,15 @@ export class ErrFailedOperation extends Error {
     super(`Failed to perform operation: ${method} : ${message}`);
   }
 }
+
+export class ErrMissingTrait extends Error {
+  public constructor(trait: string) {
+    super(`Missing trait: ${trait}`);
+  }
+}
+
+export class ErrMissingValueForTrait extends Error {
+  public constructor(trait: string) {
+    super(`Missing value for trait: ${trait}`);
+  }
+}

src/utils.ts

@@ -1,7 +1,13 @@
 import BigNumber from 'bignumber.js';
 import { DataNft } from './datanft';
 import { NftEnumType, NftType, Offer } from './interfaces';
-import { ErrFetch } from './errors';
+import {
+  ErrBadType,
+  ErrFetch,
+  ErrInvalidArgument,
+  ErrMissingTrait,
+  ErrMissingValueForTrait
+} from './errors';
 
 export function numberToPaddedHex(value: BigNumber.Value) {
   let hex = new BigNumber(value).toString(16);
@@ -64,12 +70,14 @@ export async function checkTraitsUrl(traitsUrl: string) {
   const traitsResponse = await fetch(traitsUrl);
   const traits = await traitsResponse.json();
 
+  checkStatus(traitsResponse);
+
   if (!traits.description) {
-    throw new Error('Traits description is empty');
+    throw new ErrMissingTrait(traits.description);
   }
 
   if (!Array.isArray(traits.attributes)) {
-    throw new Error('Traits attributes must be an array');
+    throw new ErrMissingTrait(traits.attributes);
   }
 
   const requiredTraits = ['Creator', 'Data Preview URL'];
@@ -81,13 +89,13 @@ export async function checkTraitsUrl(traitsUrl: string) {
         (attribute: any) => attribute.trait_type === requiredTrait
       )
     ) {
-      throw new Error(`Missing required trait: ${requiredTrait}`);
+      throw new ErrMissingTrait(requiredTrait);
     }
   }
 
   for (const attribute of traitsAttributes) {
     if (!attribute.value) {
-      throw new Error(`Empty value for trait: ${attribute.trait_type}`);
+      throw new ErrMissingValueForTrait(attribute.trait_type);
     }
   }
 }
@@ -533,7 +541,7 @@ export async function checkUrlIsUp(url: string, expectedHttpCodes: number[]) {
 }
 
 export function checkStatus(response: Response) {
-  if (response.status >= 200 && response.status <= 299) {
+  if (!(response.status >= 200 && response.status <= 299)) {
     throw new ErrFetch(response.status, response.statusText);
   }
 }

tests/traits-check.test.ts

@@ -15,8 +15,8 @@ describe('Traits strucutre test', () => {
       await checkTraitsUrl(
         'https://ipfs.io/ipfs/bafybeicbmpiehja5rjk425ol4rmrorrg5xh62vcbeqigv3zjcrfk4rtggm/metadata.json'
       );
-    } catch (error) {
-      expect(error).toStrictEqual(Error('Missing required trait: Creator'));
+    } catch (error: any) {
+      expect(error.message).toBe('Missing trait: Creator');
     }
   }, 100000);
 });