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Typescript

Subtlety: Typescript is a superset of JavaScript.

It allows you to add types to variables, functions, etc.

It is then transpiled into JavaScript for use in a browser or server.

Resources​

https://www.typescriptlang.org/docs/

Common types​

https://www.typescriptlang.org/docs/handbook/2/everyday-types.html

To do / To avoid​

https://www.typescriptlang.org/docs/handbook/declaration-files/do-s-and-don-ts.html

To study​

  • type of union/intersection

  • Type called "literal" (for types with precise values ​​"yes/no")

  • enums (example type with precise values, top, bottom, left, right)

  • The scope of the elements (public, private, protected (private but accessible by subclasses))

  • creating your own mixed types (aliases)

JavaScript code vs typescript code​

Context: We want a decision generator so that most of the time our algorithm tells us to go to work.

In Javascript​

function shouldWorkToday() {
    const randomNumber = Math.random(); // genere entre 0 et 1
    return randomNumber > 0.2; 
}


const workToday = shouldWorkToday();
console.log(workToday ? "Oui, il faut travailler aujourd'hui." : "Non, pas besoin de travailler aujourd'hui.");

In Typescript​

    // Ajout du type boolean
    function shouldWorkToday(): boolean {
    // ajout du type number
        const randomNumber: number = Math.random();  
        return randomNumber > 0.2; 
    }

    // Ajout du type boolean
    const workToday: boolean = shouldWorkToday();
    console.log(workToday ? "Oui, il faut travailler aujourd'hui." : "Non, pas besoin de travailler aujourd'hui.");