haystack-react/dist/useResolveHaystackValue.js

Project Haystack utilities for building React applications

/*
 * Copyright (c) 2021, J2 Innovations. All Rights Reserved
 */
import { second } from 'haystack-units';
import { useHaystackPoint, } from './useHaystackPoint';
import { useHaystackRecordTag } from './useHaystackRecordTag';
import { isResolvableDict, isResolvablePoint, isResolvableTag, } from './Resolvable';
/**
 * A hook to use a value from an haystack-server as react state.
 *
 * This hook should be used when input flexibility is required.
 * It is meant to abstract how data is actually retrieved/polled/written, enabling at the same time a data driven approach.
 *
 * It takes a ResolvableDict that contains the record data and a meta tag that indicates how to interact with that record to poll and write an HVal.
 * @see ResolvableDict for the options available.
 *
 * IMPORTANT: this hook requires a ClientContext to work. @see https://github.com/j2inn/haystack-nclient
 *
 * @example <caption>Here’s a usage example:</caption>
 * const [point] = useReadByFilter('point and temp and zone and sp').grid // One-shot reading the first point that matches the filter
 *
 * //Adding meta data to the dict (this could be done server side)
 * const resolvableDict1 = point?.newCopy().set('meta', {resolveType: 'point'}) as Resolvable<HNum>
 * const resolvableDict2 = point?.newCopy().set('meta', {resolveType: 'tag', readTag: 'precision'}) as Resolvable<HNum>
 *
 * // The actual state used depends on the metadata in the dict:
 * const [pointValue, setPointValue, point] = useResolveHaystackValue<HNum>(resolvableDict1)
 * const [pointPrecision, setPointPrecision, point] = useResolveHaystackValue<HNum>(resolvableDict2)
 *
 * @param resolvable Resolvable containing a record and metadata on how to resolve the value or the value itself.
 * @param pollRate poll rate for the value subscription. Expressed in seconds. Default is 5.
 * @returns a resolved value and a function to update it on the server, if the value is not resolved it is passed through.
 */
export function useResolveHaystackValue(resolvable) {
    const pollTime = resolvePollTime(resolvable);
    const isPoint = isResolvablePoint(resolvable);
    const isTag = isResolvableTag(resolvable);
    const [pointValue, writePoint, point] = useHaystackPoint(isPoint ? resolvable : undefined, pollTime, isPoint ? resolveDefaultPointWriteOpt(resolvable) : undefined);
    const [tag, writeTag, record] = useHaystackRecordTag(isTag ? resolvable : undefined, isTag ? resolvable.meta.readTag.value : undefined, pollTime);
    return isPoint
        ? [pointValue, writePoint, point]
        : isTag
            ? [tag, writeTag, record]
            : [resolvable, undefined, undefined];
}
const resolveDefaultPointWriteOpt = (resolvableDict) => {
    return {
        who: resolvableDict.meta?.writeWho?.value,
        duration: resolvableDict.meta?.writeDuration,
        level: resolvableDict.meta?.writeLevel?.value,
    };
};
const resolvePollTime = (resolvable) => {
    return isResolvableDict(resolvable)
        ? resolvable?.meta?.subscriptionPollTime?.convertTo(second).value
        : undefined;
};
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