haystack-react/dist/useHaystackPoint.js

Project Haystack utilities for building React applications

/*
 * Copyright (c) 2021, J2 Innovations. All Rights Reserved
 */
import { useEffect, useState } from 'react';
import { useClient } from './client';
import { useWatch } from './watch';
/**
 * A hook that allows using a point from an haystack server as react state.
 *
 * Important: This hooks requires a ClientContext to work. @see https://github.com/j2inn/haystack-nclient
 *
 * @example <caption>Example of usage with a numeric point.</caption>
 *
 * const point= useReadByFilter('point and temp and zone and sp').grid[0] // One-shot reading the first point that matches the filter
 * const [pointValue, setPointValue, updatedPoint] = useHaystackPoint<HNum>(point) // Using the point state
 *
 * @param originaryPoint point dict used to retrieve its id and initial value.
 * @param pollRate poll rate for the value subscription. Expressed in seconds.
 * @param writeOptions default options for the write callback.
 * @returns Returns the point value, a function to update it and the point dict.
 */
export function useHaystackPoint(originaryPoint, pollRate = 5, writeOptions) {
    const [currentValue, setCurrentValue] = useState();
    const [readValue, point] = useReadHaystackPoint(originaryPoint, pollRate);
    const write = useWriteHaystackPoint(originaryPoint?.id, writeOptions);
    const writeFunc = write
        ? async (val, options) => {
            const result = await write?.(val, options);
            setCurrentValue(val);
            return result;
        }
        : undefined;
    useEffect(() => {
        setCurrentValue(readValue);
    }, [readValue]);
    return [currentValue, writeFunc, point];
}
function useReadHaystackPoint(originalPoint, pollRate = 5) {
    const { grid: [point], isLoading, } = useWatch({
        ids: originalPoint?.id,
        pollRate: pollRate,
    });
    return isLoading
        ? [originalPoint?.curVal, originalPoint]
        : [point?.curVal, point];
}
function useWriteHaystackPoint(id, generalOptions) {
    const client = useClient();
    return id
        ? (val, options) => client.ops.pointWrite({
            id: id,
            level: generalOptions?.level ?? 17,
            who: generalOptions?.who,
            duration: generalOptions?.duration,
            ...options,
            val: val,
        })
        : undefined;
}
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