All in one single javascript

All in one single javascript

When you are ready to publish your new JavaScript project, you can combine your JavaScript files into one file to get faster page downloads, fewer GET requests and lower complexity for users to manage. Users may import your project more easily with a single script tag rather than many script tags.

npm install grunt-contrib-uglify

Here is a simple configuration that generates a single JavaScript file from three source files. Note that we generate a source map that is used to debug the JavaScript file in the browser. The source map will map code from our single script to the individual files so you can track down bugs more easily.

// Sample project configuration. grunt.initConfig(< uglify: < my_target : < options : < sourceMap : true, sourceMapName : 'sourceMap.map' >, files : < 'composite.min.js' : ['src/Model/Mux.js', 'src/Model/Hasher.js', 'src/Model/Cloner.js'] >> > >); 

Here is an example of minifying all JavaScript files in my projects src/ directory.

// Combine all files in src/ grunt.initConfig(< uglify: < all_src : < options : < sourceMap : true, sourceMapName : 'sourceMap.map' >, src : 'src/**/*.js', dest : 'composite.all.min.js' > > >); 

You can include your combined JavaScript file (composite.all.min.js) in a HTML page using the tag. Because you created a source map, when you open the debugger, you will see a list of individual files rather than a single unintelligible combined file.

Also note, if you’re starting a fresh project and like or are interested in Node.js on the backend, you may be interested in Browserify, which lets you write Node.js style modules in browser. Combining them into a single Javascript file is possible too. To learn more about this style of Javascript development, checkout the Browserify Tutorial. It may be the direction you want to head towards in the future.

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Union of Arrays in JavaScript

Union of arrays would represent a new array combining all elements of the input arrays, without repetition of elements.

Two ways are described in this tutorial. There both involve a bit of ES6 features.

ES6 Features Used

• Set : A Set object allows to store unique values. A Set object can be created from an array (or any iterable object). If the array has duplicate elements, they are eliminated.

// creating Set from an array var set_ob = new Set([1, 2, 3, 3, 4, 5, 5]); // [1, 2, 3, 4, 5] // duplicates eliminated console.log(set_ob); 

// merging of arrays using spread operator var arr1 = [1, 2, 3, 4]; var arr2 = [5, 6, 7]; // create new array // using spread operator to expand each array into individual elements var arr3 = [ . arr1, . arr2 ]; // [1, 2, 3, 4, 5, 6, 7] console.log(arr3); 

Method 1 — Merging & Eliminating Duplicates

• We first merge all arrays into one single array
• We then use the merged array to create a Set. This would eliminate duplicates.
• We then loop over the Set and create the final array.

var array_first = [1, 2, 3, 4]; var array_second = [3, 4, 5, 6]; // concatenation of the arrays var concat_array = array_first.concat(array_second); // create Set, eliminate duplicates var set_ob = new Set(concat_array); // final array that holds union var array_union = []; // iterate through each element of Set // push each element into final array for(var element of set_ob) < array_union.push(element); >// [1, 2, 3, 4, 5, 6] console.log(array_union); 

Method 2 — Using Spread Operator to Avoid Looping

The spread operator is a good way to eliminate looping. The same work is done, but with a shorter syntax.

• We use spread operator to merge arrays.
• We then create a Set from the merged array. This eliminates duplicates.
• Then again use spread operator to create an array from the Set.

var array_first = [1, 2, 3, 4]; var array_second = [3, 4, 5, 6]; // merged array var concat_array = [. array_first, . array_second]; // new array that holds union // spread expands the Set into its individual values var array_union = [. new Set(concat_array)]; // [1, 2, 3, 4, 5, 6] console.log(array_union); 

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Convert an array of objects to a single object in JavaScript

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Overview

We loop the array and use the Object.assign() method to convert an array of objects to a single object. This merges each object into a single resultant object.

The Object.assign() method also merges the properties of one or more objects into a single object.

Example

The code below demonstrates how to convert an array of objects into a single object:

let arr = [, , ];
let finalObj = <>;
console.log("The array is \n", arr);
 
// loop elements of the array
 
for(let i = 0; i < arr.length; i++ )  
Object.assign(finalObj, arr[i]);
>
 
console.log("\nAfter converting array of objects to single object");
console.log(finalObj);
 

Explanation

• Line 1: We create an array of objects.
• Line 2: We create a new object, finalObj . This will be our final merged object.
• Lines 6–8: We loop the elements of the array.
• Line 7: We use the Object.assign() method to merge all the properties of the current array object element with the finalObj object.
• After the end of the loop, all the objects of the array are converted into a single object.

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Simplest way to compile all TypeScript into one single Js file by SilvenLEAF

Ahoy there! It’s I, SilvenLEAF!! Have you ever faced an issue where you have many TypeScript files but want them all to convert into one Single JavaScript file so that you can reference it from your HTML? Then fear you not! Let’s get it done in the simplest way!! We’ll be using Webpack with TypeScript. Let’s start!

Step 0: Begin the project

Create a folder and open it in your favorite editor (mine VS Code). Then type this command on your project terminal

Bonus Step: Adding TypeScript

• init our tsconfig (make sure you already have typescript globally installed, if not type npm i -g typescript. And don’t get it confused with the previous normal npm i typescript command)

(It’ll create a .tsconfig file)

Let’s update some of the properties from that .tsconfig file

It’ll convert all TypeScript files that are inside «src» folder and output them in the «dist» folder.

Step 1: Create a Simplest project

Let’s create an «index.html» file on the root level of your project folder with this following content

   lang="en">  charset="UTF-8">  http-equiv="X-UA-Compatible" content="IE=edge">  name="viewport" content="width=device-width, initial-scale=1.0">  src="./dist/app-bundle.js" defer> Webpack with TypeScript   Let's learn Webpack with TypeScript  id="header">  id="alertBtn">Click me!   

See on line no 7, we are referencing «./dist/app-bundle.js» JavaScript file. This will be the single JavaScript file which will be compiled from all those TypeScript files.

Now let’s create a folder «src» on the root level and inside it, let’s create all our TypeScript files. Let’s create «app.ts» and «variable.ts» files (inside the «src» folder.

Inside «variable.ts» file, write the following content

export const name = 'SilvenLEAF'; 

And inside «app.ts» file write the following content

// By @SilvenLEAF import  name > from "./variable"; const alertBtn = document.querySelector('#alertBtn') as HTMLButtonElement; const header = document.querySelector('#header') as HTMLHeadingElement alertBtn.addEventListener('click', (e) =>  header.innerHTML = `Hello there, I'm $name>`; >); 

Great! We have a simple project created. Now let’s compile all those TypeScript files into one single file and test it out.

Step 2: Configure Webpack

Type the following command to install the required packages

npm i -D webpack webpack-cli typescript ts-loader 

(«npm i -D X» is the shorthand for «npm install —save-dev X»)

Now create a «webpack.config.js» file on the root level of your project folder with the following content

//webpack.config.js const path = require('path'); module.exports =  mode: "development", devtool: "inline-source-map", entry:  main: "./src/app.ts", >, output:  path: path.resolve(__dirname, './dist'), filename: "app-bundle.js" // >, resolve:  extensions: [".ts", ".tsx", ".js"], >, module:  rules: [  test: /\.tsx?$/, loader: "ts-loader" > ] > >; 

Now let’s compile them and test it out. Type this following command to compile all TypeScript files into one single file

See we are not using the «tsc» command to compile here because we are using webpack. It’ll create a single file named «app-bundle.js» inside «dist» folder. We’ll be linking this file on the «index.html». See line no 7 of «index.html» file

Now let’s test it out. Launch the «index.html» file with LIVE Server. (If you don’t have this extension installed, install it in VS Code or Atom or whatever Text Editor you are using, and run it). It’ll run that html page live on your browser. Click that «Click me!» Button and see that it’s working fine!

Before clicking the button

After clicking the button

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