DEV Community: ikechukwu1234

Mouldes, Common j's module and ES module

ikechukwu1234 — Sun, 13 Aug 2023 15:52:55 +0000

JavaScript modules: You can divide your JavaScript code into various files using modules. This makes maintaining a code base simpler. Modules also rely on the script> tag's type = "module" attribute.

modules: is Just a file, a module.One module is one script. Modules can load one another and employ specialised directives in that manner. To exchange functionality, call functions from one module into another using export and import.

The export keyword: Variables and functions marked with the export keyword should be used outside of the current module.

The import keyword: enables the importation of features from other modules.

Common j's module: The original method of packaging JavaScript code for Node.js was using Common J's module.
Common j's all of the dependencies for project are stored in one file or together in one file called node modules.

ES module: This standard, which debuted with ES6, was introduced in 2015. The goal was to provide these functionality in browsers while standardising how Js module operate

ES module each dependency is stored in its files

Modules

ikechukwu1234 — Sun, 13 Aug 2023 13:52:49 +0000

JavaScript Modules: You can divide your JavaScript code into various files using modules. This makes maintaining a code base simpler. Modules also rely on the script> tag's type = "module" attribute.

Modules: is just a file, a module.One module is one script. Modules can load one another and employ specialised directives in that manner. To exchange functionality, call functions from one module into another using export and import.

Variables and functions marked with the export keyword should be used outside of the current module.

The import keyword enables the importation of features from other modules.

Common js module:is the original method of packaging JavaScript code for Node.js was using Common J's module.

In Common J's module all of your dependencies for are stored together or in one file called node modules.

ES module: This standard, which debuted with ES6, was introduced in 2015. The goal was to provide these functionality in browsers while standardising how Js modules operate

In ES modules each dependency is stored on it's own files

TYPESCRIPT

ikechukwu1234 — Thu, 03 Aug 2023 16:16:47 +0000

TypeScript is a syntactics superset of JavaScript which adds statics types.
TypeScript being "syntactics superset" means that it shares the same base syntax as JavaScript, but add something to it.

Why should I use TypeScript?

Compilation: it a compiler of code and code error, it has error detector.
It support OOP: it support the Object Oriented Programming Language
It supports type definition from existing JavaScript:it shows the data type while your JavaScript don't when typing or programming.

TypeScript Type system
1) any Type: is a super type of all type in TypeScript. it disable type checking and effectively allows all types to be used.
2) built in type: your string:"", number:1, null, undefined
3) user defined type: the user is the one to determine the types of data to be use in the application.

Type Assignment
when creating a variable in TypeScript, there are two main ways TypeScript assigns a type:
1) Explicit:writing out the type
e.g let firstname: string = "James";
Explicit type assignment are easier to read and more intentional
2) Implicit:TypeScript will "guess" the type,based on the assigned value
let firstname = "John";
Note:Having TypeScript "guess" the type of a value is called: infer.

Implicit assignment force TypeScript to infer the value.

Implicit type assignment are shorter, faster to type,and often used when developing and testing.

Error in Type Assignment
TypeScript will throw error if data types do not match.

TypeScript syntax for variable declaration
var identifier : Type = value;

Example of Type:any
let k: any = true;
k = "string";
Example of TypeScript Arrays
TypeScript has a specific syntax for typing arrays variable.
e.g: let fruit: (string| number|null|boolean)[] = ["mango", 80, 90,null,true,false,"Edwin","Gideon"];
Example of TypeScript Tuples
Tuples is a typed array with a pre-defined length and types for each index.
Tuples help or allow each element in the array to be a known type of value.
To defined a tuple,specify the type of each element in the array
e.g:let studentscore: [string,number,string,boolean,string] = ["John", 30,"jude",true,"I love coding"];
Example of TypeScript syntax of an object
e.g: let car:{
name: string;
color: string;
wheel: number;
year: number;
}={
name: "Benz";
color: "White";
wheel: 4;
year: 2022;
};