chore(gatsby): Migrate reducers/nodes-by-type to TypeScript (#24419)

* Change nodes-by-type file extension from JS to TS

* Update reducer index import

* Update IDeleteNodeAction

* Update packages/gatsby/src/redux/reducers/nodes-by-type.ts

* properly handle undefined map.get usage

Co-authored-by: Michal Piechowiak <misiek.piechowiak@gmail.com>
Co-authored-by: gatsbybot <mathews.kyle+gatsbybot@gmail.com>
Co-authored-by: Blaine Kasten <blainekasten@gmail.com>

packages/gatsby/src/redux/reducers/index.js

@@ -1,5 +1,5 @@
 import { nodeReducer } from "./nodes"
-const nodesByType = require(`./nodes-by-type`)
+import { nodesByTypeReducer } from "./nodes-by-type"
 import { pagesReducer } from "./pages"
 import { redirectsReducer } from "./redirects"
 import { schemaReducer } from "./schema"
@@ -25,7 +25,7 @@ import { jobsReducer } from "./jobs"
 module.exports = {
   program: require(`./program`),
   nodes: nodeReducer,
-  nodesByType: nodesByType,
+  nodesByType: nodesByTypeReducer,
   resolvedNodesCache: require(`./resolved-nodes`),
   nodesTouched: nodesTouchedReducer,
   lastAction: lastAction,

packages/gatsby/src/redux/reducers/nodes-by-type.js → packages/gatsby/src/redux/reducers/nodes-by-type.ts

@@ -1,12 +1,28 @@
-const getNodesOfType = (node, state) => {
+import { IGatsbyNode, IGatsbyState, ActionsUnion } from "../types"
+
+const getNodesOfType = (
+  node: IGatsbyNode,
+  state: IGatsbyState["nodesByType"]
+): Map<string, IGatsbyNode> => {
   const { type } = node.internal
   if (!state.has(type)) {
     state.set(type, new Map())
   }
-  return state.get(type)
+  const nodeByType = state.get(type)
+
+  if (!nodeByType) {
+    throw new Error(
+      `An error occurred finding a node by it's type. This is likely a bug in gatsby. If you experience this error please open an issue.`
+    )
+  }
+
+  return nodeByType
 }
 
-module.exports = (state = new Map(), action) => {
+export const nodesByTypeReducer = (
+  state: IGatsbyState["nodesByType"] = new Map(),
+  action: ActionsUnion
+): IGatsbyState["nodesByType"] => {
   switch (action.type) {
     case `DELETE_CACHE`:
       return new Map()

packages/gatsby/src/redux/types.ts

@@ -617,9 +617,7 @@ export interface IAddChildNodeToParentNodeAction {
 
 export interface IDeleteNodeAction {
   type: `DELETE_NODE`
-  payload: {
-    id: Identifier
-  }
+  payload: IGatsbyNode
 }
 
 export interface IDeleteNodesAction {