Angular 2 Unit Tests Cannot find name describe

Question

I m following this tutorial from angular io As they said  I ve created hero spec ts file to create unit tests  import   Hero   from    hero   describe  Hero        gt      it  has name        gt        let hero  Hero    id  1  name   Super Cat        expect hero name  toEqual  Super Cat            it  has id        gt        let hero  Hero    id  1  name   Super Cat        expect hero id  toEqual 1              Unit Tests work like a charm  The problem is  I see some errors  which are mentioned in tutorial   Our editor and the compiler may complain that they don   t know what it and expect are because they lack the typing files that describe Jasmine  We can ignore those annoying complaints for now as they are harmless   And they indeed ignored it  Even though those errors are harmless  it doesn t look good in my output console when I receive bunch of them  Example of what I get   Cannot find name  describe   Cannot find name  it   Cannot find name  expect    What can I do to fix it

User · Answer

You need to install typings for jasmine   Assuming you are on a relatively recent version of typescript 2 you should be able to do   npm install --save-dev  types jasmine

User · Answer

Solution to this problem is connected with what  Pace has written in his answer  However  it doesn t explain everything so  if you don t mind  I ll write it by myself   SOLUTION   Adding this line       lt reference path             typings globals jasmine index d ts   gt    at the beginning of hero spec ts file fixes problem  Path leads to typings folder  where all typings are stored    To install typings you need to create typings json file in root of your project with following content        globalDependencies          core-js    registry dt core-js 0 0 0 20160602141332        jasmine    registry dt jasmine 2 2 0 20160621224255        node    registry dt node 6 0 0 20160807145350          And run typings install  where typings is NPM package

User · Answer

Look at the import maybe you have a cycle dependency  this was in my case the error  using import    from  jasmine   will fix the errors in the console and make the code compilable but not removes the root of devil  in my case the cycle dependency

User · Answer

In my case  the solution was to remove the typeRoots in my tsconfig json   As you can read in the TypeScript doc     If typeRoots is specified  only packages under typeRoots will be included

User · Answer

With Typescript 2 0 or later you can install types with   npm install -D  types jasmine   Then import the types automatically using the types option in tsconfig json    types     jasmine      This solution does not require import    from  jasmine   in each spec file

User · Answer

Only had to do the following to pick up  types in a Lerna Mono-repo where several node modules exist   npm install -D  types jasmine   Then in each tsconfig file of each module or app   typeRoots        node modules  types            node modules  types   lt -- I added this line

User · Answer

I m on Angular 6  Typescript 2 7  and I m using Jest framework to unit test  I had  types jest installed and added on typeRoots inside tsconfig json  But still have the display error below  i e  on terminal there is no errors      cannot find name describe   And adding the import    import    from  jest      in my case or jasmine if you re using jasmine   doesn t technically do anything  so I thought  that there is an import somewhere causing this problem  then I found  that if delete the file      tsconfig spec json    in the src  folder  solved the problem for me  As  types is imported before inside the rootTypes   I recommend you to do same and delete this file  no needed config is inside   ps  if you re in the same case as I am

User · Answer

In my case  I was getting this error when I serve the app  not when testing  I didn t realise I had a different configuration setting in my tsconfig app json file   I previously had this              include          src      ts          It was including all my  spec ts files when serving the app  I changed the include property toexclude  and added a regex to exclude all test files like this              exclude               spec ts             mocks            Now it works as expected

User · Answer

I m up to the latest as of today and found the best way to resolve this is to do nothing   no typeRoots no types no exclude no include all the defaults seem to be working just fine  Actually it didn t work right for me until I removed them all  I had    exclude          node modules      but that s in the defaults so I removed that   I had    types          node      to get past some compiler warning  But now I removed that too   The warning that shouldn t be is  error TS2304  Cannot find name  AsyncIterable   from node modules  types graphql subscription subscribe d ts  which is very obnoxious so I did this in tsconfig so that it loads it    compilerOptions          target    esnext       since it s in the esnext set  I m not using it directly so no worries here about compatibility just yet  Hope that doesn t burn me later

User · Answer

With Typescript 2 0 or later you can install types with npm install   npm install --save-dev  types jasmine   then import the types automatically using the typeRoots option in tsconfig json    typeRoots            node modules  types           This solution does not require import    from  jasmine   in each spec file

User · Answer

I ll just add Answer for what works for me in  typescript    3 2 4  I realized that jasmine in node modules  types there is a folder for ts3 1 under the jasmine type so here are the steps -   Install type jasmine npm install -D  types jasmine Add to tsconfig json jasmine ts3 1   typeRoots                node modules jasmine ts3 1     Add Jasmine to the types   types        jasmine      node       Note  No need for this import  jasmine   anymore

User · Answer

In order for TypeScript Compiler to use all visible Type Definitions during compilation  types option should be removed completely from compilerOptions field in tsconfig json file    This problem arises when there exists some types entries in compilerOptions field  where at the same time jest entry is missing   So in order to fix the problem  compilerOptions field in your tscongfig json should either include jest in types area or get rid of types comnpletely        compilerOptions          esModuleInterop   true       target    es6        module    commonjs        outDir    dist        types     reflect-metadata    jest        lt --  add jest or remove completely      moduleResolution    node        sourceMap   true         include          src      ts          exclude          node modules

User · Answer

if the error is in the  specs file app app component spec ts 7 3   error TS2304  Cannot find name  beforeEach    add this to the top of your file and npm install rxjs  import   range   from  rxjs   import   map  filter   from  rxjs operators

User · Answer

npm install  types jasmine   As mentioned in some comments the  types     jasmine   is not needed anymore  all  types packages are automatically included in compilation  since v2 1 I think    In my opinion the easiest solution is to exclude the test files in your tsconfig json like      exclude          node modules             spec ts      This works for me   Further information in the official tsconfig docs

User · Answer

I hope you ve installed -  npm install --save-dev  types jasmine   Then put following import at the top of the hero spec ts file -  import  jasmine     It should solve the problem

[unit-testing] Angular 2 Unit Tests: Cannot find name 'describe'

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