Extract getHistory query (re-use) (#1877)

packages/app-staking/src/Query/Validator.tsx

@@ -3,12 +3,13 @@
 // of the Apache-2.0 license. See the LICENSE file for details.
 
 import { I18nProps } from '@polkadot/react-components/types';
-import { BlockNumber, Exposure, Hash, SessionIndex } from '@polkadot/types/interfaces';
+import { BlockNumber, Exposure, SessionIndex } from '@polkadot/types/interfaces';
 
 import BN from 'bn.js';
 import React, { useContext, useEffect, useState } from 'react';
 import { Chart, Columar, Column } from '@polkadot/react-components';
 import { ApiContext, withCalls } from '@polkadot/react-api';
+import { getHistoric } from '@polkadot/react-api/util';
 import { formatBalance, formatNumber } from '@polkadot/util';
 
 import translate from '../translate';
@@ -47,42 +48,23 @@ function Validator ({ blockCounts, className, currentIndex, startNumber, t, vali
   const [stakeChart, setStateChart] = useState<LineData | undefined>();
 
   useEffect((): void => {
-    const numbers: BN[] = [];
-    const checkLength = (api.consts.babe
-      ? api.consts.babe.epochDuration as BlockNumber
-      : new BN(500)).muln(2).divn(3);
-    const divisor = new BN('1'.padEnd(formatBalance.getDefaults().decimals + 1, '0'));
+    api.isReady.then(async (): Promise<void> => {
+      const divisor = new BN('1'.padEnd(formatBalance.getDefaults().decimals + 1, '0'));
+      const values = await getHistoric<Exposure>(api, 'staking.stakers', [validatorId], {
+        interval: (api.consts.babe?.epochDuration as BlockNumber || new BN(500)).muln(2).divn(3),
+        max: SESSIONS,
+        startNumber
+      });
 
-    api.isReady.then((): void => {
-      let currentNumber: BN = startNumber;
-
-      // here we end up with more-or-less 6.66 days
-      while (startNumber.gtn(0) && numbers.length < SESSIONS) {
-        numbers.unshift(currentNumber);
-        currentNumber = currentNumber.sub(checkLength);
-      }
-
-      setStakeLabels(numbers.map((bn): string => formatNumber(bn)));
-
-      Promise
-        .all(numbers.map((at): Promise<Hash> =>
-          api.rpc.chain.getBlockHash(at as any)
-        ))
-        .then((hashes): Promise<Exposure[]> =>
-          Promise.all(hashes.map((hash): Promise<Exposure> =>
-            api.query.staking.stakers.at(hash, validatorId) as Promise<Exposure>
-          ))
-        )
-        .then((exposures): void => {
-          setStateChart([
-            exposures.map(({ total }): BN =>
-              total.unwrap().div(divisor))
-            // exposures.map(({ own }): BN =>
-            //   own.unwrap().div(divisor)),
-            // exposures.map(({ others }): BN =>
-            //   others.reduce((total, { value }): BN => total.add(value.unwrap()), new BN(0)).div(divisor))
-          ]);
-        });
+      setStakeLabels(values.map(([bn]): string => formatNumber(bn)));
+      setStateChart([
+        values.map(([,, { total }]): BN =>
+          total.unwrap().div(divisor))
+        // exposures.map(({ own }): BN =>
+        //   own.unwrap().div(divisor)),
+        // exposures.map(({ others }): BN =>
+        //   others.reduce((total, { value }): BN => total.add(value.unwrap()), new BN(0)).div(divisor))
+      ]);
     });
   }, []);
 

packages/react-api/src/util/hashes.ts

@@ -0,0 +1,33 @@
+// Copyright 2017-2019 @polkadot/react-api 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 { Hash } from '@polkadot/types/interfaces';
+
+import BN from 'bn.js';
+import ApiPromise from '@polkadot/api/promise';
+import { bnToBn } from '@polkadot/util';
+
+export interface HashesOptions {
+  interval: BN | number;
+  max: number;
+  startNumber: BN;
+}
+
+export default async function getHashes (api: ApiPromise, { interval, max, startNumber }: HashesOptions): Promise<[BN, Hash][]> {
+  const numbers: BN[] = [];
+  const _interval = bnToBn(interval);
+  let currentNumber: BN = startNumber;
+
+  while (numbers.length < max && currentNumber.gtn(0)) {
+    numbers.unshift(currentNumber);
+
+    currentNumber = currentNumber.sub(_interval);
+  }
+
+  const hashes = await Promise.all(
+    numbers.map((at): Promise<Hash> => api.rpc.chain.getBlockHash(at as any))
+  );
+
+  return numbers.map((bn, index): [BN, Hash] => [bn, hashes[index]]);
+}

packages/react-api/src/util/historic.ts

@@ -0,0 +1,25 @@
+// Copyright 2017-2019 @polkadot/react-api 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 { Hash } from '@polkadot/types/interfaces';
+import { Codec } from '@polkadot/types/types';
+
+import BN from 'bn.js';
+import ApiPromise from '@polkadot/api/promise';
+
+import getHashes, { HashesOptions } from './hashes';
+
+export default async function getHistory <T extends Codec> (api: ApiPromise, endpoint: string, params: any[], options: HashesOptions): Promise<[BN, Hash, T][]> {
+  const [mod, fn] = endpoint.split('.');
+  const numbers = await getHashes(api, options);
+  const results = await Promise.all(numbers.map(([, hash]): Promise<T> =>
+    api.query[mod][fn].at(hash, ...params) as Promise<T>
+  ));
+
+  return results.map((value, index): [BN, Hash, T] => [
+    numbers[index][0],
+    numbers[index][1],
+    value
+  ]);
+}

packages/react-api/src/util/index.ts

@@ -2,11 +2,15 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
+import getHashes from './hashes';
+import getHistoric from './historic';
 import intervalObservable from './intervalObservable';
 import isEqual from './isEqual';
 import triggerChange from './triggerChange';
 
 export {
+  getHashes,
+  getHistoric,
   intervalObservable,
   isEqual,
   triggerChange