How expensive are multiple requires on the same file on the same instance of Node JS?











up vote
0
down vote

favorite












My understanding of require (so far) is that it performs a traversal up the directory structure, looking for the module you're trying to import. Well, that's not exactly correct, but let's assume the directory traversal cost is negligible.



I have a module called BigModule. It has a lot of stuff in it, so there's some cost associated with loading it up with a require statement. Is importing it a hundred times a hundred times more expensive than importing it once, or is there some sort of caching mechanism which causes these scripts to share one BigModule instance? This is all happening on a single Node instance.






javascript typescript plugins







share|improve this question


























    up vote
    0
    down vote

    favorite












    My understanding of require (so far) is that it performs a traversal up the directory structure, looking for the module you're trying to import. Well, that's not exactly correct, but let's assume the directory traversal cost is negligible.



    I have a module called BigModule. It has a lot of stuff in it, so there's some cost associated with loading it up with a require statement. Is importing it a hundred times a hundred times more expensive than importing it once, or is there some sort of caching mechanism which causes these scripts to share one BigModule instance? This is all happening on a single Node instance.






    javascript typescript plugins







    share|improve this question
























      up vote
      0
      down vote

      favorite









      up vote
      0
      down vote

      favorite











      My understanding of require (so far) is that it performs a traversal up the directory structure, looking for the module you're trying to import. Well, that's not exactly correct, but let's assume the directory traversal cost is negligible.



      I have a module called BigModule. It has a lot of stuff in it, so there's some cost associated with loading it up with a require statement. Is importing it a hundred times a hundred times more expensive than importing it once, or is there some sort of caching mechanism which causes these scripts to share one BigModule instance? This is all happening on a single Node instance.






      javascript typescript plugins







      share|improve this question













      My understanding of require (so far) is that it performs a traversal up the directory structure, looking for the module you're trying to import. Well, that's not exactly correct, but let's assume the directory traversal cost is negligible.



      I have a module called BigModule. It has a lot of stuff in it, so there's some cost associated with loading it up with a require statement. Is importing it a hundred times a hundred times more expensive than importing it once, or is there some sort of caching mechanism which causes these scripts to share one BigModule instance? This is all happening on a single Node instance.






      javascript typescript plugins




      javascript typescript plugins






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 12 at 18:43









      Brent Allard

      104211




      104211
























          1 Answer
          1






          active

          oldest

          votes

















          up vote
          1
          down vote



          accepted










          require() caches calls by resolved filepath; require()ing the same file twice (even via symlink or different relative path) will not rerun the code.






          share|improve this answer





















            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',
            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%2f53268251%2fhow-expensive-are-multiple-requires-on-the-same-file-on-the-same-instance-of-nod%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








            up vote
            1
            down vote



            accepted










            require() caches calls by resolved filepath; require()ing the same file twice (even via symlink or different relative path) will not rerun the code.






            share|improve this answer

























              up vote
              1
              down vote



              accepted










              require() caches calls by resolved filepath; require()ing the same file twice (even via symlink or different relative path) will not rerun the code.






              share|improve this answer























                up vote
                1
                down vote



                accepted







                up vote
                1
                down vote



                accepted






                require() caches calls by resolved filepath; require()ing the same file twice (even via symlink or different relative path) will not rerun the code.






                share|improve this answer












                require() caches calls by resolved filepath; require()ing the same file twice (even via symlink or different relative path) will not rerun the code.







                share|improve this answer












                share|improve this answer



                share|improve this answer










                answered Nov 12 at 18:44









                SLaks

                671k13816111736




                671k13816111736






























                     

                    draft saved


                    draft discarded



















































                     


                    draft saved


                    draft discarded














                    StackExchange.ready(
                    function () {
                    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53268251%2fhow-expensive-are-multiple-requires-on-the-same-file-on-the-same-instance-of-nod%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

                    How to change which sound is reproduced for terminal bell?

                    Image
                    3 Recently upgrade to 18.10 from 18.04, and using the terminal is becoming annoying: the new alert sound is a drip ( /usr/share/sounds/gnome/default/alerts/drip.ogg ), and the previous one is still located at ( /usr/share/sounds/ubuntu/stereo/bell.ogg ). My issue is that at the gnome-terminal, when autocompleting or pressing left BOTH sounds are reproduced, at the same time. I want to just have ubuntu/stereo/bell.ogg active, not both . At the moment I have been only able to reduce the volume of the alerts (but still both are played), or turn the alerts down (but I dislike both "solutions"). gnome-terminal 18.10 teminal-bell share | improve this question
                    Read more

                    Can I use Tabulator js library in my java Spring + Thymeleaf project?

                    Image
                    0 I want to add Tabulator js to my java project. I added tabulator.min.js, tabulator.min.css to resources folder. After that added to my html page these dependencies as recommending in readme.md. <link rel="stylesheet" th:href="@{/css/tabulator.min.css}"> <script type="text/javascript" th:src="@{/js/tabulator.min.js}"></script> Now my tables view all elements, that I have in the html page, but not correct. In the documentation of Tabulator is example how to create header and table, var table = new Tabulator("#example-table", { columns:[ {title:"Name", field:"name", sorter:"string", width:200, editor:true}, {title:"Age", field:"age", sorter:"
                    Read more

                    Title Spacing in Bjornstrup Chapter, Removing Chapter Number From Contents

                    Image
                    up vote 5 down vote favorite 2 I would like to make it so that the vertical space below the title of each chapter is the same when using the Bjornstrup package (i.e. so that the descenders do not affect the spacing - as shown by the red arrow in the picture below). I think I'm fairly happy with the spacing around "A chapter", so I'd really like titles without descenders (e.g. "Contents") to have the same vertical spacing as "A chapter" below the title. I would also like to remove the large "0" in the contents title. Any help appreciated, as always. documentclass[11pt,a4paper]{book} % Packages[![enter image description here][1]][1] usepackage[left=3.5cm, right=3.5cm, top=4.3cm, bottom=4.25cm]{geometry} usepackage[utf8]{inputenc} usepackage{libertine} usepackage[libertine]{newtx
                    Read more