Type registry (#428)

* basic type registry

* register all buildin types

* get types from TypeRegistry

* Update Api constructor options to include additionalTypes

* Fix linter issue

* Style improvements and rename ApiBaseOptions to ApiOptions

* refactor Api classes constructor options

packages/types/src/codec/TypeRegistry.spec.ts

@@ -0,0 +1,38 @@
+// Copyright 2017-2018 @polkadot/types authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import TypeRegistry from './TypeRegistry';
+import Text from '../Text';
+import U32 from '../U32';
+
+describe('TypeRegistry', () => {
+  let registry: TypeRegistry;
+
+  beforeEach(() => {
+    registry = new TypeRegistry();
+  });
+
+  it('Handles non exist type', () => {
+    expect(registry.get('non-exist')).toBeUndefined();
+  });
+
+  it('Able to register type', () => {
+    registry.register(Text);
+    expect(registry.get('Text')).toBe(Text);
+  });
+
+  it('Able to register type with a different name', () => {
+    registry.register('TextRenamed', Text);
+    expect(registry.get('TextRenamed')).toBe(Text);
+  });
+
+  it('Able to register multiple types', () => {
+    registry.register({
+      Text,
+      'U32Renamed': U32
+    });
+    expect(registry.get('Text')).toBe(Text);
+    expect(registry.get('U32Renamed')).toBe(U32);
+  });
+});

packages/types/src/codec/TypeRegistry.ts

@@ -0,0 +1,40 @@
+// Copyright 2017-2018 @polkadot/types authors & contributors
+// This software may be modified and distributed under the terms
+// of the Apache-2.0 license. See the LICENSE file for details.
+
+import { Constructor } from '../types';
+import * as allTypes from '../index';
+
+export default class TypeRegistry {
+  static readonly defaultRegistry: TypeRegistry = new TypeRegistry();
+
+  private _registry: Map<string, Constructor> = new Map();
+
+  register (type: Constructor | {[name: string]: Constructor}): void;
+  register (name: string, type: Constructor): void;
+  register (arg1: string | Constructor | {[name: string]: Constructor}, arg2?: Constructor): void {
+    if (typeof arg1 === 'string') {
+      const name = arg1;
+      const type = arg2!;
+
+      this._registry.set(name, type);
+    } else if (typeof arg1 === 'function') {
+      const name = arg1.name;
+      const type = arg1;
+
+      this._registry.set(name, type);
+    } else {
+      const dict = arg1;
+
+      for (const [name, type] of Object.entries(dict)) {
+        this._registry.set(name, type);
+      }
+    }
+  }
+
+  get (name: string) {
+    return this._registry.get(name);
+  }
+}
+
+TypeRegistry.defaultRegistry.register(allTypes as any);

packages/types/src/codec/createType.ts

@@ -8,6 +8,7 @@ import { Codec, Constructor } from '../types';
 import Text from '../Text';
 import Compact from './Compact';
 import Tuple from './Tuple';
+import TypeRegistry from './TypeRegistry';
 import UInt from './UInt';
 import Vector from './Vector';
 
@@ -145,13 +146,12 @@ export function getTypeClass (value: TypeDef): Constructor {
     );
   }
 
-  // We are dynamically loading as to avoid circular dependencies
-  const Types = require('../index');
-  const Type = Types[value.type];
+  const registry = TypeRegistry.defaultRegistry;
+  const Type = registry.get(value.type);
 
   assert(Type, `Unable to determine type from '${value.type}'`);
 
-  return Type;
+  return Type!;
 }
 
 export default function createType (type: Text | string, value?: any): Codec {