From 2a5c5ce3fe65852db8752ff772a708864db4eb2d Mon Sep 17 00:00:00 2001
From: Jaco Greeff <jacogr@gmail.com>
Date: Tue, 28 Jan 2020 11:07:02 +0100
Subject: [PATCH] Only include derives with parent query (#1755)

* Only include derives with parent query

* Update CHANGELOG
---
 CHANGELOG.md                     |  1 +
 packages/api-derive/src/index.ts | 26 +++++++++++++++++++++++---
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 31c60d8099..bbbba07993 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 # 1.0.0-beta-x
 
 - **Breaking change** Drop support for Substrate v1 chain in all derives
+- Only decorate derives where relevant parent `api.query.*` is available
 - Support `.entries(arg?: any)` lookups on DoubleMaps (in addition to previously supported maps)
 - Remove un-deployed support for v11 metadata (this was decided against on Substrate)
 - Allow v9 metadata to parse even in cases where it was wrongly deployed pre-v10
diff --git a/packages/api-derive/src/index.ts b/packages/api-derive/src/index.ts
index 55c8fa10cd..9347e47787 100644
--- a/packages/api-derive/src/index.ts
+++ b/packages/api-derive/src/index.ts
@@ -23,6 +23,8 @@ import * as treasury from './treasury';
 
 export * from './type';
 
+export const derive = { accounts, balances, chain, contracts, council, democracy, elections, imOnline, session, society, staking, technicalCommittee, treasury };
+
 type DeriveSection<Section> = {
   [Method in keyof Section]: Section[Method] extends AnyFunction
     ? ReturnType<Section[Method]> // ReturnType<Section[Method]> will be the inner function, i.e. without (api) argument
@@ -34,14 +36,35 @@ type DeriveAllSections<AllSections> = {
 
 export type DeriveCustom = Record<string, Record<string, (api: ApiInterfaceRx) => (...args: any[]) => Observable<any>>>;
 
+export type ExactDerive = DeriveAllSections<typeof derive>;
+
+// Enable derive only if some of these modules are available
+const deriveAvail: Record<string, string[]> = {
+  contracts: ['contracts'],
+  council: ['council'],
+  democracy: ['democracy'],
+  elections: ['electionsPhragmen', 'elections'],
+  imOnline: ['imOnline'],
+  session: ['session'],
+  society: ['society'],
+  staking: ['staking'],
+  technicalCommittee: ['technicalCommittee'],
+  treasury: ['treasury']
+};
+
 /**
  * Returns an object that will inject `api` into all the functions inside
  * `allSections`, and keep the object architecture of `allSections`.
  */
 /** @internal */
 function injectFunctions<AllSections> (api: ApiInterfaceRx, allSections: AllSections): DeriveAllSections<AllSections> {
+  const queryKeys = Object.keys(api.query);
+
   return Object
     .keys(allSections)
+    .filter((sectionName): boolean =>
+      !deriveAvail[sectionName] || deriveAvail[sectionName].some((query): boolean => queryKeys.includes(query))
+    )
     .reduce((deriveAcc, sectionName): DeriveAllSections<AllSections> => {
       const section = allSections[sectionName as keyof AllSections];
 
@@ -61,9 +84,6 @@ function injectFunctions<AllSections> (api: ApiInterfaceRx, allSections: AllSect
     }, {} as DeriveAllSections<AllSections>);
 }
 
-export const derive = { accounts, balances, chain, contracts, council, democracy, elections, imOnline, session, society, staking, technicalCommittee, treasury };
-export type ExactDerive = DeriveAllSections<typeof derive>;
-
 // FIXME The return type of this function should be {...ExactDerive, ...DeriveCustom}
 // For now we just drop the custom derive typings
 /** @internal */