feat(http): add getHttpErrorConstructorForStatusCode

Allows you to get the constructor for a specified HTTP status code.

.travis.yml

@@ -9,8 +9,8 @@ notifications:
 # Add additional versions here as appropriate.
 node_js:
   - 'stable'
+  - '12'
   - '10'
-  - '8'
 
 # Lint errors should trigger a failure.
 before_script:

.vscode/settings.json

@@ -1,7 +1,6 @@
 // Place your settings in this file to overwrite default and user settings.
 {
   "prettier.bracketSpacing": true,
-  "prettier.eslintIntegration": true,
   "prettier.singleQuote": true,
   "prettier.semi": false,
   "eslint.enable": true,

README.md

@@ -239,6 +239,18 @@ const price = await getSomeRemotePriceThatMayOrMayNotExist().catch(
 )
 ```
 
+## `getHttpErrorConstructorForStatusCode(statusCode: number): HttpErrorConstructor`
+
+Given a status code, returns the proper error to throw.
+
+```ts
+import { getHttpErrorConstructorForStatusCode, BadRequest } from 'fejl'
+
+const ErrorCtor = getHttpErrorConstructorForStatusCode(400)
+
+ErrorCtor === BadRequest // true
+```
+
 # What's in a name?
 
 "fejl" _[fɑjl]_ is danish for _"error"_, and when pronounced in English also sounds like the word "fail".

package.json

@@ -38,28 +38,28 @@
   "homepage": "https://github.com/jeffijoe/fejl#readme",
   "dependencies": {
     "make-error": "^1.3.5",
-    "tslib": "^1.9.3"
+    "tslib": "^1.10.0"
   },
   "devDependencies": {
     "@semantic-release/condition-codeship": "^1.1.0",
-    "@semantic-release/release-notes-generator": "^7.1.4",
-    "@types/jest": "^24.0.13",
-    "@types/node": "^12.0.2",
-    "@types/rimraf": "^2.0.2",
-    "coveralls": "^3.0.3",
-    "husky": "^2.3.0",
-    "jest": "^24.8.0",
-    "lint-staged": "^8.1.7",
-    "prettier": "^1.17.1",
-    "rimraf": "^2.6.3",
-    "semantic-release": "^15.13.12",
+    "@semantic-release/release-notes-generator": "^7.3.5",
+    "@types/jest": "^24.0.24",
+    "@types/node": "^13.1.0",
+    "@types/rimraf": "^2.0.3",
+    "coveralls": "^3.0.9",
+    "husky": "^3.1.0",
+    "jest": "^24.9.0",
+    "lint-staged": "^9.5.0",
+    "prettier": "^1.19.1",
+    "rimraf": "^3.0.0",
+    "semantic-release": "^15.14.0",
     "semantic-release-conventional-commits": "^2.0.1",
     "smid": "^0.1.1",
-    "ts-jest": "^24.0.2",
-    "tslint": "^5.16.0",
+    "ts-jest": "^24.2.0",
+    "tslint": "^5.20.1",
     "tslint-config-prettier": "^1.18.0",
-    "tslint-config-standard": "^8.0.1",
-    "typescript": "^3.4.5"
+    "tslint-config-standard": "^9.0.0",
+    "typescript": "^3.7.4"
   },
   "prettier": {
     "semi": false,

src/__tests__/http.test.ts

@@ -28,3 +28,12 @@ describe('http', () => {
     expect(() => ProxyIsDown.assert(false, 'Oh well')).toThrowError(ProxyIsDown)
   })
 })
+
+describe('getHttpErrorConstructorForStatusCode', () => {
+  it('returns the correct error constructor', () => {
+    expect(http.getHttpErrorConstructorForStatusCode(403)).toBe(http.Forbidden)
+    expect(http.getHttpErrorConstructorForStatusCode(888)).toBe(
+      http.GeneralError
+    )
+  })
+})

src/__tests__/retry.test.ts

@@ -1,4 +1,5 @@
 import { retry, computeNextWaitTime } from '../retry'
+import { throws } from 'smid'
 
 test('basic', async () => {
   let i = 0
@@ -14,13 +15,15 @@ test('basic', async () => {
 
 test('exhaust', async () => {
   let count = 0
-  const err = await retry(
-    again => {
-      count++
-      throw again(new Error('Nah'))
-    },
-    { tries: 2, minTimeout: 5, factor: 1 }
-  ).catch(err => err)
+  const err = await throws(
+    retry(
+      again => {
+        count++
+        throw again(new Error('Nah'))
+      },
+      { tries: 2, minTimeout: 5, factor: 1 }
+    )
+  )
   expect(err.message).toBe('Nah')
   expect(count).toBe(2)
 })
@@ -36,13 +39,15 @@ test('wait time calculation', () => {
 
 test('tries = 0', async () => {
   let count = 0
-  const err = await retry(
-    again => {
-      count++
-      throw again(new Error('Nah'))
-    },
-    { tries: 0, minTimeout: 5, factor: 1 }
-  ).catch(err => err)
+  const err = await throws(
+    retry(
+      again => {
+        count++
+        throw again(new Error('Nah'))
+      },
+      { tries: 0, minTimeout: 5, factor: 1 }
+    )
+  )
   expect(err.message).toBe('Nah')
   expect(count).toBe(1)
 })

src/http.ts

@@ -261,6 +261,104 @@ export class NetworkAuthenticationRequired extends MakeHttpError(
   'Network Authentication Required'
 ) {}
 
+/**
+ * HTTP error constructor.
+ */
+export type HttpErrorConstructor = BaseErrorConstructor<{ statusCode: number }>
+
+/**
+ * Gets an error constructor for a HTTP status code.
+ *
+ * @param statusCode
+ */
+export function getHttpErrorConstructorForStatusCode(
+  statusCode: number
+): HttpErrorConstructor {
+  /* istanbul ignore next */
+  switch (statusCode) {
+    case 400:
+      return BadRequest
+    case 401:
+      return NotAuthenticated
+    case 402:
+      return PaymentRequired
+    case 403:
+      return Forbidden
+    case 404:
+      return NotFound
+    case 405:
+      return MethodNotAllowed
+    case 406:
+      return NotAcceptable
+    case 407:
+      return ProxyAuthenticationRequired
+    case 408:
+      return Timeout
+    case 409:
+      return Conflict
+    case 410:
+      return Gone
+    case 411:
+      return LengthRequired
+    case 412:
+      return PreconditionFailed
+    case 413:
+      return PayloadTooLarge
+    case 414:
+      return UriTooLong
+    case 415:
+      return UnsupportedMediaType
+    case 416:
+      return RequestRangeNotSatisfiable
+    case 417:
+      return ExpectationFailed
+    case 418:
+      return IAmATeapot
+    case 421:
+      return MisdirectedRequest
+    case 422:
+      return Unprocessable
+    case 423:
+      return Locked
+    case 424:
+      return FailedDependency
+    case 425:
+      return TooEarly
+    case 426:
+      return UpgradeRequired
+    case 428:
+      return PreconditionRequired
+    case 429:
+      return TooManyRequests
+    case 431:
+      return RequestHeaderFieldsTooLarge
+    case 451:
+      return UnavailableForLegalReasons
+    case 501:
+      return NotImplemented
+    case 502:
+      return BadGateway
+    case 503:
+      return ServiceUnavailable
+    case 504:
+      return GatewayTimeout
+    case 505:
+      return HttpVersionNotSupported
+    case 506:
+      return VariantAlsoNegotiates
+    case 507:
+      return InsufficientStorage
+    case 508:
+      return LoopDetected
+    case 510:
+      return NotExtended
+    case 511:
+      return NetworkAuthenticationRequired
+    default:
+      return GeneralError
+  }
+}
+
 /**
  * Builds a HTTP status code based error class.
  *
@@ -271,6 +369,6 @@ export class NetworkAuthenticationRequired extends MakeHttpError(
 function MakeHttpError(
   statusCode: number,
   message: string
-): BaseErrorConstructor<{ statusCode: number }> {
+): HttpErrorConstructor {
   return MakeErrorClass(message, { statusCode })
 }

src/make-error-class.ts

@@ -44,12 +44,12 @@ export class BaseError<A> extends CustomError {
     data: T,
     message?: string,
     attrs?: Partial<ErrorAttributes<A>>
-  ): T | never {
+  ): NonFalsy<T> {
     if (!data) {
       throw new this(message, attrs)
     }
 
-    return data
+    return data as NonFalsy<T>
   }
 
   /**
@@ -114,7 +114,12 @@ export class BaseError<A> extends CustomError {
 /**
  * Asserter function.
  */
-export type Asserter<T> = (value: any) => T | never
+export type Asserter<T> = (value: T) => NonFalsy<T>
+
+/**
+ * Non-falsy value.
+ */
+export type NonFalsy<T> = Exclude<T, false | 0 | undefined | null | ''>
 
 /**
  * Error attributes.
@@ -144,7 +149,7 @@ export interface BaseErrorConstructor<A> {
     data: T,
     message?: string,
     attrs?: Partial<ErrorAttributes<A>>
-  ): T | never
+  ): NonFalsy<T>
   /**
    * Retries the function until it does not throw the error type.
    */