Proper way to extend express Response Object using Typescript












2















I'm currently working on a project that involves Typescript 3+, and express 4+ and node 8+. I'm trying to extend express's Response object to send HTTP status codes if an API detects an error for example. I can't seem to figure out how to extend the Response object without using Middleware to define the Response extended function I want to add. I would love to be able to just use the Response prototype to define the function(s) i want to add but i don't know or can't figure out if this is possible. Here's what I've done:



projectA/declarations/express.extensions.d.ts:



import * as e from "express"

declare global {
namespace Express {
interface Response {
send100(): e.Response;
}
}
}

export {}


below is where i would like to define the prototype function definition like so but this isn't compiling...



projectA/extensions/ResponseExtensions.ts



import * as e from "express";
import { Response } from "express-serve-static-core";

Response.prototype.send100 = function(): e.Response {
var response = this as Response;
response.status(100).end();
}


and then finally consume...



ProjectB/Server.ts



import * as express from "express"

app.get('/getData'
request: express.Request,
response: express.Response) : void {

// yada yada...

response.send100();
}


I can't seem to get the ResponseExtensions.ts script to transpile, And the only other way i see to implement this is to run middleware where i define the function, but this will happen for every single request. Are there options like I'm exploring or is middleware the only way to go?



Thanks.










share|improve this question



























    2















    I'm currently working on a project that involves Typescript 3+, and express 4+ and node 8+. I'm trying to extend express's Response object to send HTTP status codes if an API detects an error for example. I can't seem to figure out how to extend the Response object without using Middleware to define the Response extended function I want to add. I would love to be able to just use the Response prototype to define the function(s) i want to add but i don't know or can't figure out if this is possible. Here's what I've done:



    projectA/declarations/express.extensions.d.ts:



    import * as e from "express"

    declare global {
    namespace Express {
    interface Response {
    send100(): e.Response;
    }
    }
    }

    export {}


    below is where i would like to define the prototype function definition like so but this isn't compiling...



    projectA/extensions/ResponseExtensions.ts



    import * as e from "express";
    import { Response } from "express-serve-static-core";

    Response.prototype.send100 = function(): e.Response {
    var response = this as Response;
    response.status(100).end();
    }


    and then finally consume...



    ProjectB/Server.ts



    import * as express from "express"

    app.get('/getData'
    request: express.Request,
    response: express.Response) : void {

    // yada yada...

    response.send100();
    }


    I can't seem to get the ResponseExtensions.ts script to transpile, And the only other way i see to implement this is to run middleware where i define the function, but this will happen for every single request. Are there options like I'm exploring or is middleware the only way to go?



    Thanks.










    share|improve this question

























      2












      2








      2


      0






      I'm currently working on a project that involves Typescript 3+, and express 4+ and node 8+. I'm trying to extend express's Response object to send HTTP status codes if an API detects an error for example. I can't seem to figure out how to extend the Response object without using Middleware to define the Response extended function I want to add. I would love to be able to just use the Response prototype to define the function(s) i want to add but i don't know or can't figure out if this is possible. Here's what I've done:



      projectA/declarations/express.extensions.d.ts:



      import * as e from "express"

      declare global {
      namespace Express {
      interface Response {
      send100(): e.Response;
      }
      }
      }

      export {}


      below is where i would like to define the prototype function definition like so but this isn't compiling...



      projectA/extensions/ResponseExtensions.ts



      import * as e from "express";
      import { Response } from "express-serve-static-core";

      Response.prototype.send100 = function(): e.Response {
      var response = this as Response;
      response.status(100).end();
      }


      and then finally consume...



      ProjectB/Server.ts



      import * as express from "express"

      app.get('/getData'
      request: express.Request,
      response: express.Response) : void {

      // yada yada...

      response.send100();
      }


      I can't seem to get the ResponseExtensions.ts script to transpile, And the only other way i see to implement this is to run middleware where i define the function, but this will happen for every single request. Are there options like I'm exploring or is middleware the only way to go?



      Thanks.










      share|improve this question














      I'm currently working on a project that involves Typescript 3+, and express 4+ and node 8+. I'm trying to extend express's Response object to send HTTP status codes if an API detects an error for example. I can't seem to figure out how to extend the Response object without using Middleware to define the Response extended function I want to add. I would love to be able to just use the Response prototype to define the function(s) i want to add but i don't know or can't figure out if this is possible. Here's what I've done:



      projectA/declarations/express.extensions.d.ts:



      import * as e from "express"

      declare global {
      namespace Express {
      interface Response {
      send100(): e.Response;
      }
      }
      }

      export {}


      below is where i would like to define the prototype function definition like so but this isn't compiling...



      projectA/extensions/ResponseExtensions.ts



      import * as e from "express";
      import { Response } from "express-serve-static-core";

      Response.prototype.send100 = function(): e.Response {
      var response = this as Response;
      response.status(100).end();
      }


      and then finally consume...



      ProjectB/Server.ts



      import * as express from "express"

      app.get('/getData'
      request: express.Request,
      response: express.Response) : void {

      // yada yada...

      response.send100();
      }


      I can't seem to get the ResponseExtensions.ts script to transpile, And the only other way i see to implement this is to run middleware where i define the function, but this will happen for every single request. Are there options like I'm exploring or is middleware the only way to go?



      Thanks.







      node.js typescript express






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 15 '18 at 5:18









      lvlosslvloss

      254




      254
























          1 Answer
          1






          active

          oldest

          votes


















          0














          The Response member of express-serve-static-core is only an interface, not a class with a prototype you can extend, so when you refer to Response as a value, TypeScript resolves it to an unrelated Response class that is part of the DOM API. The prototype object you want to extend is the response member of the express module (see this answer). It isn't declared in @types/express, but you can declare it yourself:



          declare module "express" {
          const response: Response;
          }


          Then in ResponseExtensions.ts, you can write:



          import * as e from "express";
          import { Response } from "express-serve-static-core";

          e.response.send100 = function(): e.Response {
          var response = this as Response;
          response.status(100).end();
          }





          share|improve this answer
























          • Thanks Matt! this worked out great for me.

            – lvloss
            Nov 16 '18 at 7:10













          Your Answer






          StackExchange.ifUsing("editor", function () {
          StackExchange.using("externalEditor", function () {
          StackExchange.using("snippets", function () {
          StackExchange.snippets.init();
          });
          });
          }, "code-snippets");

          StackExchange.ready(function() {
          var channelOptions = {
          tags: "".split(" "),
          id: "1"
          };
          initTagRenderer("".split(" "), "".split(" "), channelOptions);

          StackExchange.using("externalEditor", function() {
          // Have to fire editor after snippets, if snippets enabled
          if (StackExchange.settings.snippets.snippetsEnabled) {
          StackExchange.using("snippets", function() {
          createEditor();
          });
          }
          else {
          createEditor();
          }
          });

          function createEditor() {
          StackExchange.prepareEditor({
          heartbeatType: 'answer',
          autoActivateHeartbeat: false,
          convertImagesToLinks: true,
          noModals: true,
          showLowRepImageUploadWarning: true,
          reputationToPostImages: 10,
          bindNavPrevention: true,
          postfix: "",
          imageUploader: {
          brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
          contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
          allowUrls: true
          },
          onDemand: true,
          discardSelector: ".discard-answer"
          ,immediatelyShowMarkdownHelp:true
          });


          }
          });














          draft saved

          draft discarded


















          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53312889%2fproper-way-to-extend-express-response-object-using-typescript%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown

























          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          0














          The Response member of express-serve-static-core is only an interface, not a class with a prototype you can extend, so when you refer to Response as a value, TypeScript resolves it to an unrelated Response class that is part of the DOM API. The prototype object you want to extend is the response member of the express module (see this answer). It isn't declared in @types/express, but you can declare it yourself:



          declare module "express" {
          const response: Response;
          }


          Then in ResponseExtensions.ts, you can write:



          import * as e from "express";
          import { Response } from "express-serve-static-core";

          e.response.send100 = function(): e.Response {
          var response = this as Response;
          response.status(100).end();
          }





          share|improve this answer
























          • Thanks Matt! this worked out great for me.

            – lvloss
            Nov 16 '18 at 7:10


















          0














          The Response member of express-serve-static-core is only an interface, not a class with a prototype you can extend, so when you refer to Response as a value, TypeScript resolves it to an unrelated Response class that is part of the DOM API. The prototype object you want to extend is the response member of the express module (see this answer). It isn't declared in @types/express, but you can declare it yourself:



          declare module "express" {
          const response: Response;
          }


          Then in ResponseExtensions.ts, you can write:



          import * as e from "express";
          import { Response } from "express-serve-static-core";

          e.response.send100 = function(): e.Response {
          var response = this as Response;
          response.status(100).end();
          }





          share|improve this answer
























          • Thanks Matt! this worked out great for me.

            – lvloss
            Nov 16 '18 at 7:10
















          0












          0








          0







          The Response member of express-serve-static-core is only an interface, not a class with a prototype you can extend, so when you refer to Response as a value, TypeScript resolves it to an unrelated Response class that is part of the DOM API. The prototype object you want to extend is the response member of the express module (see this answer). It isn't declared in @types/express, but you can declare it yourself:



          declare module "express" {
          const response: Response;
          }


          Then in ResponseExtensions.ts, you can write:



          import * as e from "express";
          import { Response } from "express-serve-static-core";

          e.response.send100 = function(): e.Response {
          var response = this as Response;
          response.status(100).end();
          }





          share|improve this answer













          The Response member of express-serve-static-core is only an interface, not a class with a prototype you can extend, so when you refer to Response as a value, TypeScript resolves it to an unrelated Response class that is part of the DOM API. The prototype object you want to extend is the response member of the express module (see this answer). It isn't declared in @types/express, but you can declare it yourself:



          declare module "express" {
          const response: Response;
          }


          Then in ResponseExtensions.ts, you can write:



          import * as e from "express";
          import { Response } from "express-serve-static-core";

          e.response.send100 = function(): e.Response {
          var response = this as Response;
          response.status(100).end();
          }






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 15 '18 at 14:34









          Matt McCutchenMatt McCutchen

          13.9k820




          13.9k820













          • Thanks Matt! this worked out great for me.

            – lvloss
            Nov 16 '18 at 7:10





















          • Thanks Matt! this worked out great for me.

            – lvloss
            Nov 16 '18 at 7:10



















          Thanks Matt! this worked out great for me.

          – lvloss
          Nov 16 '18 at 7:10







          Thanks Matt! this worked out great for me.

          – lvloss
          Nov 16 '18 at 7:10






















          draft saved

          draft discarded




















































          Thanks for contributing an answer to Stack Overflow!


          • Please be sure to answer the question. Provide details and share your research!

          But avoid



          • Asking for help, clarification, or responding to other answers.

          • Making statements based on opinion; back them up with references or personal experience.


          To learn more, see our tips on writing great answers.




          draft saved


          draft discarded














          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53312889%2fproper-way-to-extend-express-response-object-using-typescript%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown





















































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown

































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown







          Popular posts from this blog

          Bressuire

          Vorschmack

          Quarantine