feedbacks.

Author: sainthkh

packages/driver/src/cy/commands/connectors.ts

@@ -5,7 +5,7 @@ import $dom from '../../dom'
 import $utils from '../../cypress/utils'
 import $errUtils, { CypressError } from '../../cypress/error_utils'
 
-const returnFalseIfThenable = (key, ...args) => {
+const returnFalseIfThenable = (key, ...args): boolean => {
   if ((key === 'then') && _.isFunction(args[0]) && _.isFunction(args[1])) {
     // https://github.com/cypress-io/cypress/issues/111
     // if we're inside of a promise then the promise lib will naturally

packages/driver/src/cy/commands/navigation.ts

@@ -13,10 +13,10 @@ import debugFn from 'debug'
 const debug = debugFn('cypress:driver:navigation')
 
 let id = null
-let previousDomainVisited: boolean | null = null
-let hasVisitedAboutBlank: boolean | null = null
-let currentlyVisitingAboutBlank: boolean | null = null
-let knownCommandCausedInstability: boolean | null = null
+let previousDomainVisited: boolean = false
+let hasVisitedAboutBlank: boolean = false
+let currentlyVisitingAboutBlank: boolean = false
+let knownCommandCausedInstability: boolean = false
 
 const REQUEST_URL_OPTS = 'auth failOnStatusCode retryOnNetworkFailure retryOnStatusCodeFailure retryIntervals method body headers'
 .split(' ')
@@ -675,12 +675,10 @@ export default (Commands, Cypress, cy, state, config) => {
           case 'forward': return goNumber(1)
           case 'back': return goNumber(-1)
           default:
-            $errUtils.throwErrByPath('go.invalid_direction', {
+            return $errUtils.throwErrByPath('go.invalid_direction', {
               onFail: options._log,
               args: { str },
             })
-
-            return // Error is thrown above, it exists to satisfy typescript
         }
       }
 
@@ -692,9 +690,7 @@ export default (Commands, Cypress, cy, state, config) => {
         return goString(numberOrString)
       }
 
-      $errUtils.throwErrByPath('go.invalid_argument', { onFail: options._log })
-
-      return // Error is thrown above, it exists to satisfy typescript
+      return $errUtils.throwErrByPath('go.invalid_argument', { onFail: options._log })
     },
 
     // TODO: Change the type of `any` to `Partial<Cypress.VisitOptions>`.

packages/driver/src/cypress/browser.ts

@@ -36,12 +36,15 @@ const _isBrowser = (browser, matcher, errPrefix) => {
 }
 
 // TODO: change the type of `any` to `IsBrowserMatcher`
-const isBrowser = (config, obj: any = '', errPrefix = '`Cypress.isBrowser()`') => {
+const isBrowser = (config, obj: any = '', errPrefix: string = '`Cypress.isBrowser()`') => {
   return _
   .chain(obj)
   .concat([])
   .map((matcher) => _isBrowser(config.browser, matcher, errPrefix))
-  .reduce((a: null | { isMatch: boolean, exclusive: boolean }, b) => {
+  .reduce((
+    a: null | { isMatch: boolean, exclusive: boolean },
+    b: { isMatch: boolean, exclusive: boolean },
+  ) => {
     if (!a) return b
 
     if (a.exclusive && b.exclusive) {

packages/driver/src/cypress/cookies.ts

@@ -14,7 +14,7 @@ const defaults: any = {
 
 const warnOnWhitelistRenamed = (obj, type) => {
   if (obj.whitelist) {
-    return $errUtils.throwErrByPath('cookies.whitelist_renamed', { args: { type } })
+    $errUtils.throwErrByPath('cookies.whitelist_renamed', { args: { type } })
   }
 }
 

packages/driver/src/cypress/error_utils.ts

@@ -69,7 +69,7 @@ const isChaiValidationErr = (err: Error) => {
   return _.startsWith(err.message, 'Invalid Chai property')
 }
 
-const isCypressErr = (err: Error) => {
+const isCypressErr = (err: Error): boolean => {
   return err.name === 'CypressError'
 }
 
@@ -195,7 +195,7 @@ const makeErrFromObj = (obj) => {
   return err2
 }
 
-const throwErr = (err, options: any = {}) => {
+const makeErrFromErr = (err, options: any = {}) => {
   if (_.isString(err)) {
     err = cypressErr({ message: err })
   }
@@ -222,10 +222,14 @@ const throwErr = (err, options: any = {}) => {
     _.extend(err, errProps)
   }
 
-  throw err
+  return err
+}
+
+const throwErr = (err, options: any = {}): never => {
+  throw makeErrFromErr(err, options)
 }
 
-const throwErrByPath = (errPath, options: any = {}) => {
+const throwErrByPath = (errPath, options: any = {}): never => {
   const err = errByPath(errPath, options.args)
 
   if (options.stack) {
@@ -235,7 +239,7 @@ const throwErrByPath = (errPath, options: any = {}) => {
     Error.captureStackTrace(err, throwErrByPath)
   }
 
-  throwErr(err, options)
+  throw makeErrFromErr(err, options)
 }
 
 const warnByPath = (errPath, options: any = {}) => {