Finish description of CredentialError

Author: jeskew

packages/credential-provider-base/__tests__/fromCredentials.ts

@@ -5,7 +5,9 @@ describe("fromCredentials", () => {
   it("should convert credentials into a credential provider", async () => {
     const credentials: Credentials = {
       accessKeyId: "foo",
-      secretAccessKey: "bar"
+      secretAccessKey: "bar",
+      sessionToken: "baz",
+      expiration: Math.floor(Date.now().valueOf() / 1000)
     };
     const provider: CredentialProvider = fromCredentials(credentials);
 

packages/credential-provider-base/lib/CredentialError.ts

@@ -1,7 +1,13 @@
+import { chain } from "./chain";
+
 /**
  * An error representing a failure of an individual credential provider.
  *
- * This error class has special meaning to
+ * This error class has special meaning to the {@link chain} method. If a
+ * provider in the chain is rejected with an error, the chain will only proceed
+ * to the next provider if the value of the `tryNextLink` property on the error
+ * is truthy. This allows individual providers to halt the chain and also
+ * ensures the chain will stop if an entirely unexpected error is encountered.
  */
 export class CredentialError extends Error {
   constructor(message: string, public readonly tryNextLink: boolean = true) {