lbry-desktop/ui/js/selectors/cost_info.js

import { createSelector } from 'reselect';

export const _selectState = state => state.costInfo || {};

export const selectAllCostInfoByUri = createSelector(
	_selectState,
	state => state.byUri || {}
);

export const selectCostInfoForUri = (state, props) => {
	return selectAllCostInfoByUri(state)[props.uri];
};

export const makeSelectCostInfoForUri = () => {
	return createSelector(selectCostInfoForUri, costInfo => costInfo);
};

export const selectFetchingCostInfo = createSelector(
	_selectState,
	state => state.fetching || {}
);

const selectFetchingCostInfoForUri = (state, props) => {
	return selectFetchingCostInfo(state)[props.uri];
};

export const makeSelectFetchingCostInfoForUri = () => {
	return createSelector(selectFetchingCostInfoForUri, fetching => !!fetching);
};