haystack-react/dist/useHaystackPoint.d.ts

Project Haystack utilities for building React applications

import { HDict, HGrid, HNum, HRef, HVal } from 'haystack-core';
/**
 * A Haystack point record with a specific curVal type
 */
export interface Point<Value extends HVal> extends HDict {
    /**
     * Point record id
     */
    id?: HRef;
    /**
     * Current value of the readTag
     */
    curVal?: Value;
}
/**
 * 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 declare function useHaystackPoint<Value extends HVal>(originaryPoint: Optional<Point<Value>>, pollRate?: number, writeOptions?: HaystackPointWriteOptions): [
    Optional<Value>,
    PointWriteFunc<Value> | undefined,
    Optional<Point<Value>>
];
type Optional<Value> = Value | undefined | null;
export type PointWriteFunc<Value extends HVal> = (val: Value, options?: HaystackPointWriteOptions) => Promise<HGrid<HDict>>;
/**
 * Options for a PointWrite operation,
 * See https://project-haystack.org/doc/docHaystack/Ops#pointWrite
 */
export interface HaystackPointWriteOptions {
    level?: number;
    who?: string;
    duration?: number | HNum;
}
export {};