falcor-json-graph/src/factories.js

// @flow
"use strict";
import type {
  JsonGraphAtomDefined,
  JsonGraphAtomUndefined,
  JsonGraphError,
  JsonGraphLeaf,
  JsonGraphMetadata,
  JsonGraphRef,
  JsonValue,
  Path,
  PathInvalidation,
  PathSet,
  PathValue
} from ".";

declare function atom<T: JsonValue>(
  value: T,
  props?: JsonGraphMetadata
): JsonGraphAtomDefined<T>;

declare function atom(
  value?: void,
  props?: JsonGraphMetadata
): JsonGraphAtomUndefined;

function atom(value, props) {
  const result =
    typeof value === "undefined"
      ? { $type: "atom" }
      : { $type: "atom", value: value };
  return props ? Object.assign({}, props, result) : result;
}

function undefinedAtom(): JsonGraphAtomUndefined {
  return { $type: "atom" };
}

module.exports = {
  ref: function ref(path: Path, props?: JsonGraphMetadata): JsonGraphRef {
    const result = { $type: "ref", value: path };
    return props ? Object.assign({}, props, result) : result;
  },
  atom: atom,
  undefinedAtom: undefinedAtom,
  error: function error(
    errorValue: string,
    props?: JsonGraphMetadata
  ): JsonGraphError {
    const result = { $type: "error", value: errorValue };
    return props ? Object.assign({}, props, result) : result;
  },
  pathValue: function pathValue(
    path: PathSet,
    value: JsonGraphLeaf
  ): PathValue {
    return { path: path, value: value };
  },
  pathInvalidation: function pathInvalidation(path: PathSet): PathInvalidation {
    return { path: path, invalidated: true };
  }
};