Nodejs require for importing modules and more

In nodejs the require global is something that will end up being used often in projects as a way to make use of built in as well as custom made nodejs modules. There is more to it then just a way to load modules though, it can also be used as a way to load json files and other assets, so lets take a look at some nodejs require examples today.

1 - nodejs require can be used for loading built in modules

So the nodejs require can be used to load any of the nodejs built in modules such as the file system and operating system modules. These modules are built into nodejs itself so no additional software needs to be installed globally or into a project folder with npm, or copied ans passed into an external javaScript file.

let os = require('os');
console.log(os.platform());

In the above example I am using the operating system module to find out the current operating system platform that the script is running on. There is a wide range of other built in modules to work with so be sure to check those out first to see if they work out okay before looking into npm packages.

2 - nodejs require can also be used to load custom modules

So the nodejs require global can also be used to load an external modules in the from of an external javaScript file. When writing an external javaScript file there is the module.exports property this is of interest when it comes to making what is exported a function.

A function is a kind of object in javaScript so the function can be extended with additional properties as well.

let api = function (a, b) {
    return a + b;
};
api.myFunc = api;
module.exports = api

once I have an external javaScript file that exports something I can then bring it into another file with the nodejs require global, just like that of built in modules, only now I pass a relative path to the external javaScript file.

let mm = require('./mymod.js');
console.log( mm(5,1) ); // 6
console.log( mm.myFunc(5,1) ); // 6

3 - require can also be used to load json

Another thing about the node.js require global is that it can also be used as a way to read and parse external JSON data. This is often a quicker option to using the file system module and JSON.parse, however it can still produce an error in the event that the file contains invalid JSON data.

{
    "foo": "bar"
}

let json = require('./foo.json');
console.log(json.foo); // 'bar'

4 - Conclusion

So the the require method is the main way that I go about making use of additional modules when making some kind of node script. On top of the core functionally that has to do with loading built in and user space javaScript modules, it can also be used as a way to load JOSN files. However require may not always be the best option for making use of some kind of external script, or resource. There is also the file system methods that can also be used to load JSON by reading the plain text first, at which point the JSON.parse method can be used in actually catch block to parse the text. Also if I want to run a script that is written in a language other than javaScript of course I can not do that with require, but I can use the child process module to call the binary that would be used to run such a script and then pass the script as an argument for that binary.