docs: update readme with v3.0 API (#84)

README.md

@@ -10,19 +10,11 @@ This is intended to support the proposed [Decentralized Identifiers](https://w3c
 
 The library does not implement any specific DID method, but allows DID method implementors to release npm packages that applications can add.
 
-## Breaking changes (0.1.0)
-
-This removes the global resolver. We've learnt that this ended up causing many problems. Instead you should now instantiate a Resolver object and use that to resolve did's within your consuming app/library.
-
-### Changes required for developers of DID resolvers
-
-You now no longer register your DID resolvers using the global `registerMethod()` function. Instead export the resolver function and show how to configure it in a local resolver object.
-
 ## Configure `Resolver` object
 
 You are now required to preconfigure a resolver during instantiation. The `Resolver` constructor expects a registry of methods mapped to a resolver function. For example: 
 ```js
-{ 
+{
   ethr: resolve,
   web: resolve
 }
@@ -49,6 +41,29 @@ const resolver = new Resolver({
 const resolver = new Resolver(ethrResolver)
 ```
 
+### Using legacy DID Method resolvers
+DID Method resolvers created before version `3.0.0` of this library can be passed as legacy resolvers.
+```js
+import { Resolver } from 'did-resolver'
+import web from 'web-did-resolver'
+import sov from 'sov-did-resolver'
+
+//returns an object of { methodName: resolveFunction}
+webResolver = web.getResolver()
+sovResolver = sov.getResolver()
+
+//If you are using multiple methods you need to flatten them into one object
+const resolver = new Resolver({}, {
+  legacyResolvers: {
+    ...webResolver,
+    ...sovResolver,
+  }
+})
+
+//If you are using one method you can simply pass the result of getResolver( into the constructor
+const resolver = new Resolver(ethrResolver)
+```
+
 ## Resolving a DID document
 
 The resolver presents a simple `resolve()` function that returns a ES6 Promise returning the DID document.
@@ -72,7 +87,9 @@ The built in Cache can be enabled by passing in a `true` value to the constructo
 const resolver = new DIDResolver({
   ethr,
   web
-}, true)
+}, {
+  cache: true
+})
 ```
 
 Here is an example using `js-cache` which has not been tested.
@@ -93,14 +110,16 @@ const customCache : DIDCache = (parsed, resolve) => {
 const resolver = new DIDResolver({
   ethr,
   web
-}, customCache)
+}, {
+  cache: customCache
+})
 ```
 
 ## Implementing a DID method
 
 Each DID method will have its own methods for looking up an identifier on its respective blockchain or other decentralized storage mechanism.
 
-To avoid misconfiguration, method implementers should export a `getResolver()` function which returns an object mapping the method name to a `resolve(did: string, parsed: ParsedDID, didResolver: DIDResolver)` function. e.g. `{ ethr: resolve }`.
+To avoid misconfiguration, method implementers should export a `getResolver()` function which returns an object mapping the method name to a `resolve(did: string, parsed: ParsedDID, didResolver: DIDResolver, options: DIDResolutionOptions)` function. e.g. `{ ethr: resolve }`.
 
 The resolve function should accept a did string, and an object of type [ParsedDID](https://github.com/decentralized-identity/did-resolver/blob/develop/src/resolver.ts#L51)
 
@@ -109,15 +128,20 @@ export function getResolver() {
   async function resolve(
     did: string,
     parsed: ParsedDID,
-    didResolver: Resolver
+    didResolver: Resolver,
+    options: DIDResolutionOptions
   ): Promise<DIDDocument> {
     console.log(parsed)
     // {method: 'mymethod', id: 'abcdefg', did: 'did:mymethod:abcdefg/some/path#fragment=123', path: '/some/path', fragment: 'fragment=123'}
     const didDoc = ...// lookup doc
     // If you need to lookup another did as part of resolving this did document, the primary DIDResolver object is passed in as well
     const parentDID = await didResolver.resolve(...)
-    //
-    return didDoc
+    // Return the DIDResolutionResult object
+    return {
+      didResolutionMetadata: { contentType: 'application/did+ld+json' },
+      didDocument: didDoc
+      didDocumentMetadata: { ... }
+    }
   }
 
   return { myMethod: resolve }