switch components reducer to use Map for state

packages/gatsby/src/internal-plugins/query-runner/gatsby-node.js

@@ -3,7 +3,7 @@ const { watchComponent } = require(`./query-watcher`)
 let components = {}
 
 exports.onCreatePage = ({ page, store }) => {
-  const component = store.getState().components[page.componentPath]
+  const component = store.getState().components.get(page.componentPath)
 
   if (components[component.componentPath]) {
     return

packages/gatsby/src/internal-plugins/query-runner/page-query-runner.js

@@ -125,7 +125,7 @@ const runQueriesForPathnames = pathnames => {
         ({
           id: page.path,
           jsonName: page.jsonName,
-          query: store.getState().components[page.componentPath].query,
+          query: store.getState().components.get(page.componentPath).query,
           isPage: true,
           componentPath: page.componentPath,
           context: {

packages/gatsby/src/internal-plugins/query-runner/query-compiler.js

@@ -103,7 +103,7 @@ class Runner {
     // run babel on code in node_modules). Otherwise the component will throw
     // an error in the browser of "graphql is not defined".
     files = files.concat(
-      Object.keys(store.getState().components).map(c => normalize(c))
+      Array.from(store.getState().components.keys(), c => normalize(c))
     )
     files = _.uniq(files)
 

packages/gatsby/src/internal-plugins/query-runner/query-watcher.js

@@ -94,7 +94,7 @@ const runQueriesForPageComponent = componentPath => {
     queue.push({
       id: page.path,
       jsonName: page.jsonName,
-      query: store.getState().components[componentPath].query,
+      query: store.getState().components.get(componentPath).query,
       isPage: true,
       context: {
         ...page,
@@ -141,7 +141,7 @@ const watch = rootDir => {
 
       // If a component previously with a query now doesn't — update the
       // store.
-      const noQueryComponents = Object.values(components).filter(
+      const noQueryComponents = Array.from(components.values()).filter(
         c => c.query !== `` && !queries.has(c.componentPath)
       )
       noQueryComponents.forEach(({ componentPath }) => {
@@ -177,7 +177,7 @@ const watch = rootDir => {
           //
           // If the query has changed, set the new query in the
           // store and run its queries.
-          if (components[id] && text !== components[id].query) {
+          if (components.has(id) && text !== components.get(id).query) {
             boundActionCreators.replaceComponentQuery({
               query: text,
               componentPath: id,

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

@@ -1,30 +1,29 @@
 const _ = require(`lodash`)
 const normalize = require(`normalize-path`)
 
-module.exports = (state = {}, action) => {
+module.exports = (state = new Map(), action) => {
   switch (action.type) {
     case `DELETE_CACHE`:
-      return {}
+      return new Map()
     case `CREATE_PAGE`:
       action.payload.componentPath = normalize(action.payload.component)
-      state[action.payload.componentPath] = _.merge(
-        { query: `` },
-        state[action.payload.componentPath],
-        {
+      state.set(
+        action.payload.componentPath,
+        _.merge({ query: `` }, state.get(action.payload.componentPath), {
           componentPath: action.payload.componentPath,
-        }
+        })
       )
       return state
     case `DELETE_PAGE`:
       action.payload.componentPath = normalize(action.payload.component)
-      delete state[action.payload.componentPath]
+      state.delete(action.payload.componentPath)
       return state
     case `REPLACE_COMPONENT_QUERY`:
       action.payload.componentPath = normalize(action.payload.componentPath)
-      state[action.payload.componentPath] = {
-        ...state[action.payload.componentPath],
+      state.set(action.payload.componentPath, {
+        ...state.get(action.payload.componentPath),
         query: action.payload.query,
-      }
+      })
       return state
   }