scan()

Accumulate upstream values and emit each intermediate accumulator.

Import

import { scan } from "@graphrefly/ts/operators";

Signature

function scan(
  reducer: (acc: T, v: S) => T,
  seed: T,
): Operator<S, T>

Parameters

Parameter	Type	Description
reducer	(acc: T, v: S) => T	Reducer called with the previous accumulator and each upstream value.
seed	T	Initial accumulator value.

Returns

An operator that emits the accumulator after every input value.

Example

import { graph } from "@graphrefly/ts/graph";
import { scan } from "@graphrefly/ts/operators";

const g = graph();
const values = g.state(1);
const total = g.initNode(scan((sum: number, value: number) => sum + value, 0), [values]);

Source

packages/ts/src/graph/operators.ts