add types for gatsby-node-helpers package

Author: saikojosh

src/@types/gatsby-node-helpers/index.d.ts

@@ -0,0 +1,22 @@
+declare module 'gatsby-node-helpers' {
+	import Gatsby from 'gatsby';
+
+	export interface ICreateNodeHelpersArgs {
+		typePrefix: string;
+	}
+
+	export function nodeFactory(data: object): Gatsby.NodeInput;
+
+	export function createNodeFactory(type: string): typeof nodeFactory;
+	export function generateTypeName(type: string): string;
+	export function generateNodeId(type: string, id: string): string;
+
+	export interface INodeHelpers {
+		createNodeFactory: typeof createNodeFactory;
+		generateTypeName: typeof generateTypeName;
+		generateNodeId: typeof generateNodeId;
+	}
+
+	export function createNodeHelpers(args: ICreateNodeHelpersArgs): INodeHelpers;
+	export default createNodeHelpers;
+}