Typescript wrapping types












0















I have some factory method which is making some computations and manipulations. Also I have a generic method doSomething. I don't wanna to specify type for doSomething each time. I would like to do it once for factory method and then get it each time with already assigned type



function factory<T>(t: T){
// some computations

return {method: doSomething<T>} <- this is what I wanna do
}

// Generic
function<T extends object>doSomething(): T{
//complex stuff, a lot of lambdas
}


How from factory method I can return doSomething with allready assigned type?










share|improve this question



























    0















    I have some factory method which is making some computations and manipulations. Also I have a generic method doSomething. I don't wanna to specify type for doSomething each time. I would like to do it once for factory method and then get it each time with already assigned type



    function factory<T>(t: T){
    // some computations

    return {method: doSomething<T>} <- this is what I wanna do
    }

    // Generic
    function<T extends object>doSomething(): T{
    //complex stuff, a lot of lambdas
    }


    How from factory method I can return doSomething with allready assigned type?










    share|improve this question

























      0












      0








      0


      1






      I have some factory method which is making some computations and manipulations. Also I have a generic method doSomething. I don't wanna to specify type for doSomething each time. I would like to do it once for factory method and then get it each time with already assigned type



      function factory<T>(t: T){
      // some computations

      return {method: doSomething<T>} <- this is what I wanna do
      }

      // Generic
      function<T extends object>doSomething(): T{
      //complex stuff, a lot of lambdas
      }


      How from factory method I can return doSomething with allready assigned type?










      share|improve this question














      I have some factory method which is making some computations and manipulations. Also I have a generic method doSomething. I don't wanna to specify type for doSomething each time. I would like to do it once for factory method and then get it each time with already assigned type



      function factory<T>(t: T){
      // some computations

      return {method: doSomething<T>} <- this is what I wanna do
      }

      // Generic
      function<T extends object>doSomething(): T{
      //complex stuff, a lot of lambdas
      }


      How from factory method I can return doSomething with allready assigned type?







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      asked Nov 22 '18 at 22:11









      Oskar WoźniakOskar Woźniak

      119113




      119113
























          1 Answer
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          You can't specify the type parameter of a generic function without calling it. So doSomething<T> is not acceptable; only doSomething<T>() is allowed. Luckily, you can just return a concrete function that calls the generic function with the proper type parameter specified. Like this:



          function factory<T extends object>(t: T) {
          // some computations
          return { method: ()=>doSomething<T>() }
          }

          // Generic, note generic parameter comes after the function name
          declare function doSomething<T extends object>(): T;


          Let's see if it works:



          const ret = factory({a: "hey"}).method();
          // const ret: { a: string }


          Looks good to me. Hope that helps; good luck!






          share|improve this answer























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            1 Answer
            1






            active

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            active

            oldest

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            active

            oldest

            votes









            1














            You can't specify the type parameter of a generic function without calling it. So doSomething<T> is not acceptable; only doSomething<T>() is allowed. Luckily, you can just return a concrete function that calls the generic function with the proper type parameter specified. Like this:



            function factory<T extends object>(t: T) {
            // some computations
            return { method: ()=>doSomething<T>() }
            }

            // Generic, note generic parameter comes after the function name
            declare function doSomething<T extends object>(): T;


            Let's see if it works:



            const ret = factory({a: "hey"}).method();
            // const ret: { a: string }


            Looks good to me. Hope that helps; good luck!






            share|improve this answer




























              1














              You can't specify the type parameter of a generic function without calling it. So doSomething<T> is not acceptable; only doSomething<T>() is allowed. Luckily, you can just return a concrete function that calls the generic function with the proper type parameter specified. Like this:



              function factory<T extends object>(t: T) {
              // some computations
              return { method: ()=>doSomething<T>() }
              }

              // Generic, note generic parameter comes after the function name
              declare function doSomething<T extends object>(): T;


              Let's see if it works:



              const ret = factory({a: "hey"}).method();
              // const ret: { a: string }


              Looks good to me. Hope that helps; good luck!






              share|improve this answer


























                1












                1








                1







                You can't specify the type parameter of a generic function without calling it. So doSomething<T> is not acceptable; only doSomething<T>() is allowed. Luckily, you can just return a concrete function that calls the generic function with the proper type parameter specified. Like this:



                function factory<T extends object>(t: T) {
                // some computations
                return { method: ()=>doSomething<T>() }
                }

                // Generic, note generic parameter comes after the function name
                declare function doSomething<T extends object>(): T;


                Let's see if it works:



                const ret = factory({a: "hey"}).method();
                // const ret: { a: string }


                Looks good to me. Hope that helps; good luck!






                share|improve this answer













                You can't specify the type parameter of a generic function without calling it. So doSomething<T> is not acceptable; only doSomething<T>() is allowed. Luckily, you can just return a concrete function that calls the generic function with the proper type parameter specified. Like this:



                function factory<T extends object>(t: T) {
                // some computations
                return { method: ()=>doSomething<T>() }
                }

                // Generic, note generic parameter comes after the function name
                declare function doSomething<T extends object>(): T;


                Let's see if it works:



                const ret = factory({a: "hey"}).method();
                // const ret: { a: string }


                Looks good to me. Hope that helps; good luck!







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 23 '18 at 1:50









                jcalzjcalz

                24.1k22142




                24.1k22142






























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