fix(sdk-core): update DID regex to allow digits in method names per W3C spec

- Update DID validation regex to allow digits in method names per W3C spec
- Add test cases for DIDs with numeric method names (did:key2:, did:btc1:)
- Update JSDoc to reflect digits allowed in DID method names
- Add package-lock.json to .gitignore to prevent future commits
- Add changeset for DID format validation feature

Author: aspiers

.changeset/did-format-validation.md

@@ -0,0 +1,9 @@
+---
+"@hypercerts-org/sdk-core": minor
+---
+
+Add `isValidDid()` utility function for DID format validation
+
+- Validates DID format (did:method:identifier) with support for numeric method names per W3C spec
+- Exported from `@hypercerts-org/sdk-core` for consumer use
+- `BlobOperationsImpl` constructor now validates `repoDid` and throws `ValidationError` for invalid formats

.gitignore

@@ -18,6 +18,7 @@ coverage.json
 npm-debug.log*
 yarn-debug.log*
 yarn-error.log*
+package-lock.json
 .DS_Store
 /.idea
 stats.html

packages/sdk-core/src/core/types.ts

@@ -26,7 +26,7 @@ export type DID = string;
  * Validates that a string is a valid DID format.
  *
  * DIDs must follow the format: `did:<method>:<method-specific-id>`
- * where method is lowercase letters and the identifier contains
+ * where method is lowercase letters and digits, and the identifier contains
  * alphanumeric characters plus `.`, `_`, `:`, `%`, and `-`.
  *
  * @param did - The string to validate
@@ -44,9 +44,9 @@ export type DID = string;
  */
 export function isValidDid(did: string): boolean {
   // DID format: did:<method>:<method-specific-id>
-  // Method: lowercase letters only
+  // Method: lowercase letters and digits (per W3C DID Core spec)
   // Identifier: alphanumeric plus . _ : % -
-  return /^did:[a-z]+:[a-zA-Z0-9._:%-]+$/.test(did);
+  return /^did:[a-z0-9]+:[a-zA-Z0-9._:%-]+$/.test(did);
 }
 
 /**

packages/sdk-core/tests/core/types.test.ts

@@ -30,6 +30,18 @@ describe("isValidDid", () => {
     it("should accept DID with hyphens and underscores", () => {
       expect(isValidDid("did:example:my-test_id")).toBe(true);
     });
+
+    it("should accept DID with method containing digits", () => {
+      expect(isValidDid("did:key2:abc123")).toBe(true);
+    });
+
+    it("should accept DID with method containing multiple digits", () => {
+      expect(isValidDid("did:btc1:xyz789")).toBe(true);
+    });
+
+    it("should accept DID with method that is all digits", () => {
+      expect(isValidDid("did:123:identifier")).toBe(true);
+    });
   });
 
   describe("invalid DIDs", () => {
@@ -57,10 +69,6 @@ describe("isValidDid", () => {
       expect(isValidDid("did:PLC:abc123")).toBe(false);
     });
 
-    it("should reject method with numbers", () => {
-      expect(isValidDid("did:plc2:abc123")).toBe(false);
-    });
-
     it("should reject random URL", () => {
       expect(isValidDid("https://example.com")).toBe(false);
     });