Add initial MultiAddress impl.

packages/types/src/generic/MultiAddress.ts

@@ -0,0 +1,44 @@
+// Copyright 2017-2020 @polkadot/types authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import { Registry } from '../types';
+
+import { isString, u8aConcat } from '@polkadot/util';
+import { decodeAddress } from '@polkadot/util-crypto';
+
+import Enum from '../codec/Enum';
+
+export default class MultiAddress extends Enum {
+  constructor (registry: Registry, value?: unknown) {
+    super(registry, {
+      Id: 'AccountId',
+      Index: 'Compact<AccountIndex>',
+      Raw: 'Bytes',
+      // eslint-disable-next-line sort-keys
+      Address32: 'H256',
+      // eslint-disable-next-line sort-keys
+      Address20: 'H160'
+    }, MultiAddress._decodeMultiAddress(value as string));
+  }
+
+  private static _decodeMultiAddress (value?: unknown): unknown {
+    if (isString(value)) {
+      try {
+        const u8a = decodeAddress(value.toString());
+
+        return u8aConcat(new Uint8Array(u8a.length <= 8 ? 1 : 0), u8a);
+      } catch (error) {
+        // ignore, not a valid ss58 address
+      }
+    }
+
+    return value;
+  }
+
+  /**
+   * @description Returns the string representation of the value
+   */
+  public toString (): string {
+    return this.value.toString();
+  }
+}

packages/types/src/generic/index.ts

@@ -10,4 +10,5 @@ export { default as GenericCall } from './Call';
 export { default as GenericConsensusEngineId } from './ConsensusEngineId';
 export { default as GenericEvent } from './Event';
 export { default as GenericLookupSource } from './LookupSource';
+export { default as GenericMultiAddress } from './MultiAddress';
 export { default as GenericVote } from './Vote';

packages/types/src/interfaces/runtime/definitions.ts

@@ -81,6 +81,7 @@ export default {
     LookupSource: 'GenericLookupSource',
     LookupTarget: 'AccountId',
     ModuleId: 'LockIdentifier',
+    MultiAddress: 'GenericMultiAddress',
     Moment: 'u64',
     OpaqueCall: 'Bytes',
     Origin: 'DoNotConstruct<Origin>',