@pond-ts/react API Reference
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    Function useCurrent

    • Subscribe to a live source and return the current value of a reducer mapping, updated on a throttle. Equivalent to useSnapshot(src).tail(tail).reduce(mapping) but with one subscription, one memo, and narrow per-entry types inherited from TimeSeries.reduce.

      const current = useCurrent(live, { cpu: 'avg', host: 'unique' });
      //   ^ { cpu: number | undefined;
      //       host: ReadonlyArray<ScalarValue> | undefined }

      const recent = useCurrent(live, { cpu: 'p95' }, { tail: '30s' });

      Returns a stable-shape object while the source has no events (every mapped field is undefined), so destructuring on first render is safe.

      Reference stability: when a new event push leaves the reduce output structurally unchanged (same scalar values, same-length arrays with same elements), the previous result reference is returned unchanged. Downstream useMemo([value]) and useEffect([value]) only re-run when the value actually changes — no need for a manual .slice() or deep-compare equality helper at the call site.

      Type Parameters

      • S extends SeriesSchema
      • const Mapping extends
            | Readonly<
                Record<
                    string,
                    | AggregateReducer
                    | Readonly<
                        {
                            from: ValueColumnsForSchema<S>[number]["name"];
                            kind?: ScalarKind | undefined;
                            using: AggregateFunctionsForKind<
                                Extract<
                                    ValueColumnsForSchema<(...)>[number],
                                    ColumnDef<(...)[(...)], ScalarKind>,
                                >["kind"],
                            >;
                        },
                    >,
                >,
            >
            | {
                readonly [K in string
                | number
                | symbol]: K extends ValueColumnsForSchema<S>[number]["name"]
                    ?
                        | Readonly<
                            {
                                from: ValueColumnsForSchema<S>[number]["name"];
                                kind?: ScalarKind;
                                using: AggregateFunctionsForKind<
                                    Extract<
                                        ValueColumnsForSchema<(...)>[number],
                                        ColumnDef<(...)[(...)], ScalarKind>,
                                    >["kind"],
                                >;
                            },
                        >
                        | AggregateFunctionsForKind<
                            ColumnKindByName<ValueColumnsForSchema<S>, K & string>,
                        >
                    : string extends K
                        ? | AggregateReducer
                        | Readonly<
                            {
                                from: ValueColumnsForSchema<S>[number]["name"];
                                kind?: ScalarKind | undefined;
                                using: AggregateFunctionsForKind<
                                    Extract<(...)[(...)], ColumnDef<(...), (...)>>["kind"],
                                >;
                            },
                        >
                        : Readonly<
                            {
                                from: ValueColumnsForSchema<S>[number]["name"];
                                kind?: ScalarKind;
                                using: AggregateFunctionsForKind<
                                    Extract<
                                        ValueColumnsForSchema<(...)>[number],
                                        ColumnDef<(...)[(...)], ScalarKind>,
                                    >["kind"],
                                >;
                            },
                        >
            }

      Parameters

      Returns ReduceResult<S, Mapping>

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