refactor: cleanup to reduce file size and add tests

Author: boschni

.babelrc

@@ -11,7 +11,15 @@
     "@babel/preset-typescript",
     "@babel/react"
   ],
-  "plugins": ["babel-plugin-transform-async-to-promises"],
+  "plugins": [
+    [
+      "const-enum",
+      {
+        "transform": "constObject"
+      }
+    ],
+    "babel-plugin-transform-async-to-promises"
+  ],
   "env": {
     "test": {
       "presets": [
@@ -24,7 +32,15 @@
           }
         ]
       ],
-      "plugins": ["babel-plugin-transform-async-to-promises"]
+      "plugins": [
+        [
+          "const-enum",
+          {
+            "transform": "constObject"
+          }
+        ],
+        "babel-plugin-transform-async-to-promises"
+      ]
     }
   }
 }

.eslintrc

@@ -25,6 +25,7 @@
       {
         "ignoreParameters": true
       }
-    ]
+    ],
+    "no-shadow": "error"
   }
 }

package.json

@@ -63,6 +63,7 @@
     "@typescript-eslint/parser": "^3.6.1",
     "babel-eslint": "^10.1.0",
     "babel-jest": "^26.0.1",
+    "babel-plugin-const-enum": "^1.0.1",
     "babel-plugin-transform-async-to-promises": "^0.8.15",
     "cross-env": "^7.0.2",
     "eslint": "7.x",

src/core/query.ts

@@ -9,6 +9,7 @@ import {
   isDocumentVisible,
   isOnline,
   isServer,
+  isValidTimeout,
   noop,
   replaceEqualDeep,
   sleep,
@@ -27,7 +28,6 @@ import { QueryObserver, UpdateListener } from './queryObserver'
 // TYPES
 
 interface QueryInitConfig<TResult, TError> {
-  queryCache: QueryCache
   queryKey: ArrayQueryKey
   queryHash: string
   config: QueryConfig<TResult, TError>
@@ -65,11 +65,11 @@ export interface RefetchOptions {
   throwOnError?: boolean
 }
 
-export enum ActionType {
-  Failed = 'Failed',
-  Fetch = 'Fetch',
-  Success = 'Success',
-  Error = 'Error',
+const enum ActionType {
+  Failed,
+  Fetch,
+  Success,
+  Error,
 }
 
 interface FailedAction {
@@ -118,7 +118,7 @@ export class Query<TResult, TError> {
 
   constructor(init: QueryInitConfig<TResult, TError>) {
     this.config = init.config
-    this.queryCache = init.queryCache
+    this.queryCache = init.config.queryCache!
     this.queryKey = init.queryKey
     this.queryHash = init.queryHash
     this.notifyGlobalListeners = init.notifyGlobalListeners
@@ -150,7 +150,7 @@ export class Query<TResult, TError> {
 
     this.clearGcTimeout()
 
-    if (this.cacheTime === Infinity || this.observers.length > 0) {
+    if (this.observers.length > 0 || !isValidTimeout(this.cacheTime)) {
       return
     }
 
@@ -234,16 +234,16 @@ export class Query<TResult, TError> {
   onInteraction(type: 'focus' | 'online'): void {
     // Execute the first observer which is enabled,
     // stale and wants to refetch on this interaction.
-    const observer = this.observers.find(
+    const staleObserver = this.observers.find(
       observer =>
         observer.isStale() &&
         observer.config.enabled &&
         ((observer.config.refetchOnWindowFocus && type === 'focus') ||
           (observer.config.refetchOnReconnect && type === 'online'))
     )
 
-    if (observer) {
-      observer.fetch().catch(noop)
+    if (staleObserver) {
+      staleObserver.fetch().catch(noop)
     }
 
     // Continue any paused fetch

src/core/queryCache.ts

@@ -84,11 +84,13 @@ export class QueryCache {
     this.queries = {}
     this.queriesArray = []
     this.isFetching = 0
+
+    this.notifyGlobalListeners = this.notifyGlobalListeners.bind(this)
   }
 
   private notifyGlobalListeners(query?: Query<any, any>) {
     this.isFetching = this.getQueries().reduce(
-      (acc, query) => (query.state.isFetching ? acc + 1 : acc),
+      (acc, q) => (q.state.isFetching ? acc + 1 : acc),
       0
     )
 
@@ -229,13 +231,10 @@ export class QueryCache {
     }
 
     const query = new Query<TResult, TError>({
-      queryCache: this,
       queryKey,
       queryHash,
       config,
-      notifyGlobalListeners: query => {
-        this.notifyGlobalListeners(query)
-      },
+      notifyGlobalListeners: this.notifyGlobalListeners,
     })
 
     if (!this.config.frozen) {
@@ -312,9 +311,11 @@ export class QueryCache {
       ...config,
     })
 
-    let query
     try {
-      query = this.buildQuery<TResult, TError>(queryKey, configWithoutRetry)
+      const query = this.buildQuery<TResult, TError>(
+        queryKey,
+        configWithoutRetry
+      )
       if (options?.force || query.isStaleByTime(config.staleTime)) {
         await query.fetch(undefined, configWithoutRetry)
       }

src/core/queryObserver.ts

@@ -1,4 +1,9 @@
-import { getStatusProps, isServer, isDocumentVisible } from './utils'
+import {
+  getStatusProps,
+  isServer,
+  isDocumentVisible,
+  isValidTimeout,
+} from './utils'
 import type { QueryResult, QueryObserverConfig } from './types'
 import type { Query, Action, FetchMoreOptions, RefetchOptions } from './query'
 import type { QueryCache } from './queryCache'
@@ -90,9 +95,7 @@ export class QueryObserver<TResult, TError> {
     // Update refetch interval if needed
     if (
       config.enabled !== prevConfig.enabled ||
-      config.refetchInterval !== prevConfig.refetchInterval ||
-      config.refetchIntervalInBackground !==
-        prevConfig.refetchIntervalInBackground
+      config.refetchInterval !== prevConfig.refetchInterval
     ) {
       this.updateRefetchInterval()
     }
@@ -163,16 +166,15 @@ export class QueryObserver<TResult, TError> {
 
     this.clearStaleTimeout()
 
-    const staleTime = this.config.staleTime || 0
     const { isStale, updatedAt } = this.currentResult
 
-    if (isStale || staleTime === Infinity) {
+    if (isStale || !isValidTimeout(this.config.staleTime)) {
       return
     }
 
     const timeElapsed = Date.now() - updatedAt
-    const timeUntilStale = staleTime - timeElapsed
-    const timeout = Math.max(timeUntilStale, 0)
+    const timeUntilStale = this.config.staleTime - timeElapsed
+    const timeout = Math.max(timeUntilStale, 1)
 
     this.staleTimeoutId = setTimeout(() => {
       this.updateIsStale()
@@ -186,12 +188,7 @@ export class QueryObserver<TResult, TError> {
 
     this.clearRefetchInterval()
 
-    if (
-      !this.config.enabled ||
-      !this.config.refetchInterval ||
-      this.config.refetchInterval < 0 ||
-      this.config.refetchInterval === Infinity
-    ) {
+    if (!this.config.enabled || !isValidTimeout(this.config.refetchInterval)) {
       return
     }
 
@@ -309,6 +306,8 @@ export class QueryObserver<TResult, TError> {
   }
 
   onQueryUpdate(action: Action<TResult, TError>): void {
+    const { type } = action
+
     // Store current result and get new result
     const prevResult = this.currentResult
     this.updateResult()
@@ -317,11 +316,11 @@ export class QueryObserver<TResult, TError> {
 
     // We need to check the action because the state could have
     // transitioned from success to success in case of `setQueryData`.
-    if (action.type === 'Success' && currentResult.isSuccess) {
+    if (type === 2) {
       config.onSuccess?.(currentResult.data!)
       config.onSettled?.(currentResult.data!, null)
       this.updateTimers()
-    } else if (action.type === 'Error' && currentResult.isError) {
+    } else if (type === 3) {
       config.onError?.(currentResult.error!)
       config.onSettled?.(undefined, currentResult.error!)
       this.updateTimers()

src/core/tests/utils.test.tsx

@@ -1,4 +1,4 @@
-import { deepEqual, replaceEqualDeep } from '../utils'
+import { deepEqual, replaceEqualDeep, deepIncludes } from '../utils'
 import { setConsole, queryCache } from '..'
 import { queryKey } from '../../react/tests/utils'
 
@@ -29,6 +29,20 @@ describe('core/utils', () => {
     setConsole(console)
   })
 
+  describe('deepIncludes', () => {
+    it('should return `true` if a includes b', () => {
+      const a = { a: { b: 'b' }, c: 'c', d: [{ d: 'd ' }] }
+      const b = { a: { b: 'b' }, c: 'c', d: [] }
+      expect(deepIncludes(a, b)).toEqual(true)
+    })
+
+    it('should return `false` if a does not include b', () => {
+      const a = { a: { b: 'b' }, c: 'c', d: [] }
+      const b = { a: { b: 'b' }, c: 'c', d: [{ d: 'd ' }] }
+      expect(deepIncludes(a, b)).toEqual(false)
+    })
+  })
+
   describe('deepEqual', () => {
     it('should return `true` for equal objects', () => {
       const a = { a: { b: 'b' }, c: 'c', d: [{ d: 'd ' }] }

src/core/utils.ts

@@ -54,7 +54,7 @@ export function functionalUpdate<TInput, TOutput>(
 
 function stableStringifyReplacer(_key: string, value: any): unknown {
   if (typeof value === 'function') {
-    throw new Error('Cannot stringify non JSON value')
+    throw new Error()
   }
 
   if (isObject(value)) {
@@ -89,6 +89,10 @@ export function deepIncludes(a: any, b: any): boolean {
   return false
 }
 
+export function isValidTimeout(value: any): value is number {
+  return typeof value === 'number' && value >= 0 && value !== Infinity
+}
+
 export function isDocumentVisible(): boolean {
   // document global can be unavailable in react native
   if (typeof document === 'undefined') {

src/hydration/tests/hydration.test.tsx

@@ -134,8 +134,7 @@ describe('dehydration and rehydration', () => {
     // Exact shape is not important here, just that staleTime and cacheTime
     // (and any future other config) is not included in it
     const dehydratedQuery = dehydrated?.queries.find(
-      dehydratedQuery =>
-        (dehydratedQuery?.config?.queryKey as Array<string>)[0] === 'string'
+      query => (query?.config?.queryKey as Array<string>)[0] === 'string'
     )
     expect(dehydratedQuery).toBeTruthy()
     expect(dehydratedQuery?.config.cacheTime).toBe(undefined)
@@ -180,8 +179,7 @@ describe('dehydration and rehydration', () => {
     // This is testing implementation details that can change and are not
     // part of the public API, but is important for keeping the payload small
     const dehydratedQuery = dehydrated?.queries.find(
-      dehydratedQuery =>
-        (dehydratedQuery?.config?.queryKey as Array<string>)[0] === 'string'
+      query => (query?.config?.queryKey as Array<string>)[0] === 'string'
     )
     expect(dehydratedQuery).toBeUndefined()
 

src/react/ReactQueryCacheProvider.tsx

@@ -7,7 +7,7 @@ import {
 } from '../core'
 import { QueryCache } from '../core/queryCache'
 
-export const queryCacheContext = React.createContext(defaultQueryCache)
+const queryCacheContext = React.createContext(defaultQueryCache)
 
 export const useQueryCache = () => React.useContext(queryCacheContext)