Graphlet

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Graph ​

Graph is the core runtime class.

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

const graph = new Graph(
  [
    ["step1", ["step2"]],
    ["step2", []]
  ] as const,
  {
    initial: "step1"
  }
);

Constructor ​

ts
new Graph(entries, options);

Entries ​

ts
[
  [node, nextNodes]
]

Example:

ts
[
  ["step1", ["step2", "step3"]],
  ["step2", []],
  ["step3", []]
]

Options ​

ts
{
  initial?: Node;
  context?: Context;
}

current ​

Returns the current node.

ts
graph.current();

getSnapshot ​

Returns the current runtime snapshot.

ts
graph.getSnapshot();

Snapshot shape:

ts
{
  current: Node;
  next: Node[];
  context: Context;
  history: Node[];
}

getNodes ​

Returns all nodes.

ts
graph.getNodes();

getNext ​

Returns next nodes.

ts
graph.getNext();
graph.getNext("step3");

getEdges ​

Returns all edges.

ts
graph.getEdges();

Example:

ts
[
  ["step1", "step2"],
  ["step1", "step3"]
]

hasNode ​

Checks if a node exists.

ts
graph.hasNode("step1");

assertNode ​

Throws if a node does not exist.

ts
graph.assertNode("step1");

canGo ​

Checks if transition from one node to another exists.

ts
graph.canGo("step1", "step2");

canGoTo ​

Checks if transition from current node to target node exists.

ts
graph.canGoTo("step2");

goTo ​

Moves to another node if transition is allowed.

ts
graph.goTo("step2");

With payload:

ts
graph.goTo("step2", {
  source: "button"
});

Success result:

ts
{
  ok: true,
  from: "step1",
  to: "step2",
  current: "step2",
  payload: {
    source: "button"
  }
}

Failure result:

ts
{
  ok: false,
  reason: "TRANSITION_NOT_ALLOWED",
  from: "step1",
  to: "step5"
}

Failure reasons:

ts
"UNKNOWN_NODE"
"TRANSITION_NOT_ALLOWED"

getContext ​

Returns current context.

ts
graph.getContext();

setContext ​

Updates context.

ts
graph.setContext(nextContext);

Or with updater:

ts
graph.setContext((ctx) => ({
  ...ctx,
  completed: [...ctx.completed, graph.current()]
}));

getHistory ​

Returns visited nodes.

ts
graph.getHistory();

canGoBack ​

Checks if back() can be called successfully.

ts
graph.canGoBack();

back ​

Moves to previous node in history.

ts
graph.back();

clearHistory ​

Clears history and keeps only the current node.

ts
graph.clearHistory();

reset ​

Returns graph to initial node and resets history.

ts
graph.reset();

subscribe ​

Subscribes to graph changes.

ts
const unsubscribe = graph.subscribe((snapshot, event) => {
  console.log(snapshot);
  console.log(event);
});

unsubscribe();