Files
api/packages/api-derive/src/session/indexes.ts
T
2020-09-17 16:31:06 +02:00

95 lines
2.9 KiB
TypeScript

// Copyright 2017-2020 @polkadot/api-derive authors & contributors
// SPDX-License-Identifier: Apache-2.0
import { ApiInterfaceRx } from '@polkadot/api/types';
import { ActiveEraInfo, EraIndex, Moment, SessionIndex } from '@polkadot/types/interfaces';
import { DeriveSessionIndexes } from '../types';
import { Observable, of } from 'rxjs';
import { map } from 'rxjs/operators';
import { Option, u32 } from '@polkadot/types';
import { isFunction } from '@polkadot/util';
import { memo } from '../util';
function isEraOpt (era: Option<EraIndex> | EraIndex): era is Option<EraIndex> {
return isFunction((era as Option<EraIndex>).unwrapOrDefault);
}
// parse into Indexes
function parse ([activeEra, activeEraStart, currentEra, currentIndex, validatorCount]: [EraIndex, Option<Moment>, EraIndex, SessionIndex, u32]): DeriveSessionIndexes {
return {
activeEra,
activeEraStart,
currentEra,
currentIndex,
validatorCount
};
}
// query for previous V2
function queryNoActive (api: ApiInterfaceRx): Observable<DeriveSessionIndexes> {
return api.queryMulti<[Option<EraIndex> | EraIndex, SessionIndex, u32]>([
api.query.staking.currentEra,
api.query.session.currentIndex,
api.query.staking.validatorCount
]).pipe(
map(([currentEraOpt, currentIndex, validatorCount]): DeriveSessionIndexes => {
const currentEra = isEraOpt(currentEraOpt)
? currentEraOpt.unwrapOrDefault()
: currentEraOpt;
return parse([
currentEra,
api.registry.createType('Option<Moment>'),
currentEra,
currentIndex,
validatorCount
]);
})
);
}
// query based on latest
function query (api: ApiInterfaceRx): Observable<DeriveSessionIndexes> {
return api.queryMulti<[Option<ActiveEraInfo>, Option<EraIndex>, SessionIndex, u32]>([
api.query.staking.activeEra,
api.query.staking.currentEra,
api.query.session.currentIndex,
api.query.staking.validatorCount
]).pipe(
map(([activeOpt, currentEra, currentIndex, validatorCount]): DeriveSessionIndexes => {
const { index, start } = activeOpt.unwrapOrDefault();
return parse([
index,
start,
currentEra.unwrapOrDefault(),
currentIndex,
validatorCount
]);
})
);
}
// empty set when none is available
function empty (api: ApiInterfaceRx): Observable<DeriveSessionIndexes> {
return of(parse([
api.registry.createType('EraIndex'),
api.registry.createType('Option<Moment>'),
api.registry.createType('EraIndex'),
api.registry.createType('SessionIndex', 1),
api.registry.createType('u32')
]));
}
export function indexes (instanceId: string, api: ApiInterfaceRx): () => Observable<DeriveSessionIndexes> {
return memo(instanceId, (): Observable<DeriveSessionIndexes> =>
api.query.session && api.query.staking
? isFunction(api.query.staking.activeEra)
? query(api)
: queryNoActive(api)
: empty(api)
);
}