Implement hasCapability and fix typo in builder.ts (#53)

* Fix typo * Implement `hasCapability` * Fix typo in test
ucan-wg · Mar 16, 2022 · 979ea39 · 979ea39
1 parent 92d2281
commit 979ea39
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Showing 3 changed files with 26 additions and 3 deletions.
diff --git a/src/attenuation.ts b/src/attenuation.ts
@@ -55,6 +55,29 @@ export function isCapabilityEscalation<A>(obj: unknown): obj is CapabilityEscala
     && util.hasProp(obj, "capability")
 }
 
+export function hasCapability<Cap>(semantics: CapabilitySemantics<Cap>, capability: CapabilityWithInfo<Cap>, ucan: Chained): CapabilityWithInfo<Cap> | false {
+  for (const cap of capabilities(ucan, semantics)) {
+    if (isCapabilityEscalation(cap)) {
+      continue
+    }
+
+    const delegatedCapability = semantics.tryDelegating(cap.capability, capability.capability)
+
+    if (isCapabilityEscalation(delegatedCapability)) {
+      continue
+    }
+
+    if (delegatedCapability != null) {
+      return {
+        info: delegateCapabilityInfo(capability.info, cap.info),
+        capability: delegatedCapability,
+      }
+    }
+  }
+
+  return false
+}
+
 export function canDelegate<A>(semantics: CapabilitySemantics<A>, capability: A, ucan: Chained): boolean {
   for (const cap of capabilities(ucan, semantics)) {
     if (isCapabilityEscalation(cap)) {

diff --git a/src/builder.ts b/src/builder.ts
@@ -117,13 +117,13 @@ export class Builder<State extends Partial<BuildableState>> {
     if (!isFinite(seconds) || seconds <= 0) {
       throw new TypeError(`Expected seconds to be a positive number, but got ${seconds}`)
     }
-    return this.withExpiraton(Math.floor(Date.now() / 1000) + seconds)
+    return this.withExpiration(Math.floor(Date.now() / 1000) + seconds)
   }
 
   /**
    * @param expiration The UTCTime timestamp (in seconds) for when the UCAN should expire.
    */
-  withExpiraton(expiration: number): Builder<State & { expiration: number }> {
+  withExpiration(expiration: number): Builder<State & { expiration: number }> {
     if (typeof expiration !== "number" || !isFinite(expiration)) {
       throw new TypeError(`Expected expiration as number, but got ${expiration}`)
     }

diff --git a/tests/builder.test.ts b/tests/builder.test.ts
@@ -17,7 +17,7 @@ describe("Builder", () => {
     const ucan = await Builder.create()
       .issuedBy(alice)
       .toAudience(bob.did())
-      .withExpiraton(expiration)
+      .withExpiration(expiration)
       .withNotBefore(notBefore)
       .withFact(fact1, fact2)
       .withNonce()