From 6c9fe763e14e85ff030ea4977fe7c6d7e3ce4a3d Mon Sep 17 00:00:00 2001
From: Jaco Greeff <jacogr@gmail.com>
Date: Mon, 15 Jul 2019 11:13:59 +0200
Subject: [PATCH] Export meta on consts (#1119)

* Export meta on consts

* Comment around meta extension

* Add meta manual check
---
 .../src/consts/fromMetadata/index.ts            | 17 +++++++++++++----
 .../src/consts/fromMetadata/types.ts            | 11 ++++++-----
 packages/api/src/checkTypes.manual.ts           |  6 ++++++
 3 files changed, 25 insertions(+), 9 deletions(-)

diff --git a/packages/api-metadata/src/consts/fromMetadata/index.ts b/packages/api-metadata/src/consts/fromMetadata/index.ts
index e00647b1e2..70244e5e98 100644
--- a/packages/api-metadata/src/consts/fromMetadata/index.ts
+++ b/packages/api-metadata/src/consts/fromMetadata/index.ts
@@ -2,12 +2,12 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
+import { Constants, ConstantCodec, ModuleConstants } from './types';
+
 import { createType } from '@polkadot/types';
 import Metadata from '@polkadot/types/Metadata';
 import { stringCamelCase } from '@polkadot/util';
 
-import { Constants, ModuleConstants } from './types';
-
 /**
  * Retrieve the parameter types (module constants) from the runtime metadata.
  *
@@ -22,8 +22,17 @@ export default function fromMetadata (metadata: Metadata): Constants {
     const { name } = moduleMetadata;
 
     // For access, we change the index names, i.e. Democracy.EnactmentPeriod -> democracy.enactmentPeriod
-    result[stringCamelCase(name.toString())] = moduleMetadata.constants.reduce((newModule, constantMeta): ModuleConstants => {
-      newModule[stringCamelCase(constantMeta.name.toString())] = createType(constantMeta.type, constantMeta.value);
+    result[stringCamelCase(name.toString())] = moduleMetadata.constants.reduce((newModule, meta): ModuleConstants => {
+      const codec = createType(meta.type, meta.value);
+      const ccodec = codec as ConstantCodec;
+
+      // This is not a perfect idea, however as it stands with number-only constants on the metadata
+      // does not have any effect. However, this could become problematic in cases where items are
+      // exposed that contain their own metadata. As of now, the compatibility with current, e.g.
+      // storage is the driving factor, one consistent way of handling interfaces
+      ccodec.meta = meta;
+      newModule[stringCamelCase(meta.name.toString())] = ccodec;
+
       return newModule;
     }, {} as unknown as ModuleConstants);
 
diff --git a/packages/api-metadata/src/consts/fromMetadata/types.ts b/packages/api-metadata/src/consts/fromMetadata/types.ts
index 0e14ac0b69..a3552ed0ff 100644
--- a/packages/api-metadata/src/consts/fromMetadata/types.ts
+++ b/packages/api-metadata/src/consts/fromMetadata/types.ts
@@ -3,11 +3,12 @@
 // of the Apache-2.0 license. See the LICENSE file for details.
 
 import { Codec } from '@polkadot/types/types';
+import { ModuleConstantMetadata as MetaV6 } from '@polkadot/types/Metadata/v6/Constants';
 
-export interface ModuleConstants {
-  [key: string]: Codec;
+export interface ConstantCodec extends Codec {
+  meta: MetaV6;
 }
 
-export interface Constants {
-  [key: string]: ModuleConstants; // Will hold modules returned by state_getMetadata
-}
+export type ModuleConstants = Record<string, ConstantCodec>;
+
+export type Constants = Record<string, ModuleConstants>;
diff --git a/packages/api/src/checkTypes.manual.ts b/packages/api/src/checkTypes.manual.ts
index 1ec2f9d695..e5dc317cbb 100644
--- a/packages/api/src/checkTypes.manual.ts
+++ b/packages/api/src/checkTypes.manual.ts
@@ -49,6 +49,12 @@ export default async function test (): Promise<void> {
     console.log('current author:', header.author);
   });
 
+  // constants has actual value & metadata
+  console.log(
+    api.consts.balances.creationFee.toHex(),
+    api.consts.balances.creationFee.meta.documentation.map((s) => s.toString()).join('')
+  );
+
   const transfer = api.tx.balances.transfer(keyring.bob.address, 12345);
 
   console.log('transfer as Method', transfer as IMethod);