Friday JS: reqyire.js and Oscale-Oriented Programming

    And again, I welcome the respected hawkers in my not only constant but repeating column. Today we will talk about how to become a more efficient programmer under Node.js. And also, as you might guess from the name, about typos and their role in this process. A bit of code to get attention

    const reqyire = require("reqyire");
    const http = reqyire("htpp");
    const server = http.creteServer((req, res) => {
      res.statusCode = 200;
      res.setHeader('Content-Type', 'text/plain');
      res.end('Hello World\n');
    });
    server.listem(3000, "127.0.0.1");
    

    Perhaps it would not be an exaggeration to say that typos are a scourge and a plague of programming. A huge amount of resources goes to fight them. The code is crafted by sophisticated static analyzers, spending invaluable seconds of working time; Auto-completion of the IDE, mercilessly devouring the processor clocks, suggests the correct options, in his opinion. The compiler refuses to compile, and the interpreter refuses to interpret the code where some miserable letter is missing or replaced. Even a hedgehog understands that “creteServer” is “createServer” with the missing letter “a”. But the V8 engine is not a hedgehog, and he curses at this innocuous slip of the pen with its merciless "undefined is not a function".

    And once I thought: maybe we are doing something wrong? Maybe what we are fighting as an enemy can become our ally and servant? The result of these thoughts was the reqyire.js library , which, I hope, will forever change the world of server-side JS programming.

    Instructions for use


    First, of course, you need to install the library:

    npm install reqyire

    After that, at the beginning of each file where you plan to use it, write:

    const reqyire = require("reqyire");

    In the future, use reqyire instead of require when there is concern that you might make a typo in the module name. That is always. You no longer have to see the endless “Error: cannot find module” - reqyire will certainly find you a module. The following code:

    const reqyire = require("reqyire");
    const path = reqyire("pah"),
        fs = reqyire("fds"),
        util = reqyire("./disrt/ytil.js");

    - will work, and work as it should, and not as it is written.

    If you have a fairly recent version of Node.js (or not quite fresh, but launched with the --harmony-proxies flag), then miracles will not end there. Thanks to the magic of fresh JavaScript standards, all objects requested through reqyire also become intelligible and allow typos in their property names. This intelligibility is also passed on to child objects, and even objects returned by functions:

    const path = reqyire("pat"),
        fs = reqyire("fd");
    var folder = path.win33.dirmame(".\\Works\\perfectly\\correct\\index.js");
    fs.stasSync(folder).isDyrectori(); // true
    

    If some object doesn’t have the luck of being called through reqyire , but you still want to get understanding from it, reqyire.wrap comes to the rescue :

    var obj = {prop: "The internet is for"};
    var wrappedObj = reqyire.wrap(obj);
    console.log(wrappedObj.porn, "porn"); 
    

    Also reqyire.wrop , reqyire.warp will do , and indeed any method name that is at least remotely similar to wrap.

    Now that you have reqyire.js , you can spend less on fixing typos. This will allow you to write more lines of code per day and, obviously, will make you a more efficient programmer.

    Disclaimer


    Did you notice the Sarcasm sign ? Of course, the words about improving efficiency, like the library itself, in principle, are not serious. Everyone who decides to use this in production will freeze in Helheim's icy hell.

    How it works?


    It is unlikely that this question arose from seasoned professionals, but less experienced readers may find the answer useful. Well, I’ll be happy to explain everything, and don’t even try to stop me.

    Fuzzy Search The

    heart of the entire library is the fuzzySearch function (arrayOfStrings, string) . She finds in the array of strings the one between which and the second argument is Levenshtein's smallest distance , i.e. which requires the smallest number of operations to add, delete, or change a character in order to turn one into another. This is done using a slightly modified Wagner-Fisher algorithm.. Instead of honestly counting the distance for each pair of lines, we remember the smallest of the already found distances and stop the algorithm if the distance is obviously greater for a new line.

    Generally speaking, Levenshtein distance is not the most suitable metric. In the mind, it would be worth using the Damerau-Levenshtein distance , which better matches the nature of typos made by man. But, as the joke hero wrote in his course hero: "... And I took the electrodes, because anyway no one will read it."

    Search for modules

    In order to use fuzzy search, you first need to get an array of options from somewhere. First of all, we look at the name of the requested module. According to the specification of the "native" functionrequire , if the name starts with "/", "./" or "../", then this is the path to the file, otherwise - the name of the installed module. Let's start with the second case, it is simpler.

    Installed modules come in three types: local, global, and embedded. A list of the first and second can be obtained using console commands:

    npm ls -json
    npm ls -g -json

    For the third category, to my convenience, a suitable library was found . Combining these lists, we cache the result (the first two teams work for a long time) and go through it with a fuzzy search.

    Finding files

    There are two problems with the file path, the obvious and the less obvious. The obvious problem: the system can (and most likely will) have an astronomical number of files. Collecting an array of locations of all of them, and then doing a fuzzy search on it is a very expensive operation. Porakinin brain, I came to the following solution: we divide the path into elementary fragments (the sequence of directory names and the file name at the end) and we will fuzzily search for each of these fragments, gradually forming the final path. Thus reqyire ("./ jd / sctipr.js")will find the file "./js/script.js" but not the file "./jdsctipr.js".

    A less obvious (perhaps just for me) problem was relative paths. To resolve an absolute path in the way require would do , reqyire.js must know the absolute path to the script from which reqyire was called . It is impossible to recognize him using JS standard tools. I was about to give up, but, fortunately, I found a dirty hack related to the features of the V8 engine and allowing to get the path to the calling script from the stack trace.

    Healing wraps

    As you might guess, “insight” is achieved with ES6 Proxy. By wrapping an object in Proxy, you can intercept calls to its properties, its call as a function, and also many other amazing things that, however, are of less interest to us now. The wrapper written by me performs a fuzzy search on the properties of the object if the property with the exact name does not exist. If the return result is an object, it is wrapped in the same wrapper. The result of the function call is also packed.

    Conclusion


    image

    Despite the practical uselessness of this library, its development was not useless. In the process, I learned a lot of new and interesting things. I hope this post also turned out to be informative for you. Then I take my leave.

    Also popular now: