Update for 18-11-21 21:30
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Javascript is probably the most popular language in existance. It is an
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interpreted, typeless language
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== Node ==
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== Backend ==
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See [[Node.js.wiki]] for the core runtime of backend js (node)
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See [[../tech/express.js.wiki]]
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See [[Node.js.wiki]]
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@ -53,3 +53,57 @@ where a pointer is assigned then later called through the pointer.
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The file system can be read in two modes, either in a block or non blocking
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mode (similar to async calls in C#)
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Below is an example of exactly that. The 'Sync' calls are ones that are done in
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a blocking manner
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{{{
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//import read file
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const { readFile, readFileSync } = require('fs');
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//read the file, blocking
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const txt = readFileSync('./sample.txt', 'utf8');
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console.log(txt);
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//or read the file on a seperate thread
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//the third argument is the file name, encoding, then the function (which gets
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//passed both the error object, and the contents of the file)
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readFile('./sample.txt', 'utf8', (err, txt) => {
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//stuff to do after we get the file
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console.log(txt)
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});
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console.log('this is called after the fact');
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}}}
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== Packages ==
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Node.js's package manager is npm. It can download packages for you to use in
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your project. To start using npm in a project, run `npm init -y` to setup a
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package.json file, which is how npm keeps track of files it needs. Now to
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install a framework (for example, express), run `npm install express`, and
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thats all that is needed
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To include a package (which includes the several built in packages), use the
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`require()` syntax, and pass it a string argument of the name of the module.
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This system is how you can use several files on one project. To include a
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module called 'my-module', you first create a my-module.js file, the add this
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to the top of your code
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{{{
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const myModule = require('./my-module');
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console.log(myModule);
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}}}
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Then in the module file you must export code from it. In the module file, add
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the following
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{{{
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module.exports = {
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myvar : 'some value'
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}
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}}}
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Now myModule.myvar will return 'some value'. You can use functions and the like
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here to make easy to import functionality.
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8
tech/express.js.wiki
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tech/express.js.wiki
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= Express.js =
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Express.js is a web framework for node.js, for making full stack web
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applications.
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== Hello World ==
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Below is a hello world application, that responds on the root directory.
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