Context

Context is user-defined data stored inside the graph runtime.

Graphlet does not interpret context. It only stores it, returns it in snapshots and notifies listeners when it changes.

Create graph with context

import { Graph } from "@graphlet/core";

type Node = "profile" | "review";

type Payload = {
  source: "button" | "form";
};

type Context = {
  profile: {
    name: string;
    email: string;
  };
};

const graph = new Graph<Node, Payload, Context>(
  [
    ["profile", ["review"]],
    ["review", ["profile"]]
  ],
  {
    initial: "profile",
    context: {
      profile: {
        name: "",
        email: ""
      }
    }
  }
);

Read context

graph.getContext();

Update context by value

graph.setContext({
  profile: {
    name: "Ada Lovelace",
    email: "ada@example.com"
  }
});

Update context with function

graph.setContext((ctx) => ({
  ...ctx,
  profile: {
    ...ctx.profile,
    name: "Ada Lovelace"
  }
}));

Context in snapshot

graph.getSnapshot();

{
  current: "profile",
  next: ["review"],
  context: {
    profile: {
      name: "Ada Lovelace",
      email: "ada@example.com"
    }
  },
  history: ["profile"]
}

Context update event

graph.subscribe((snapshot, event) => {
  if (event.type === "context") {
    console.log(event.previousContext);
    console.log(event.context);
  }
});