https://code-garage.fr › blog › quelles-sont-les-differences-entre-var-let-et-const-en...
Quelles sont les différences entre var, let et const en JavascriptJavascript a été créé à l'origine avec un seul mot-clé pour définir une variable, ce mot réservé est : var. Mais depuis la version 6 (ECMAScript 2015) de la spécification du langage, deux nouveaux mot-clés sont apparus : let et const.
https://developer.mozilla.org › fr › docs › Web › JavaScript › Reference › Statements › let
let - JavaScript | MDN - MDN Web DocsL'instruction let permet de déclarer une variable dont la portée est celle du bloc courant, éventuellement en initialisant sa valeur. Exemple interactif. Syntaxe. js. let var1 [= valeur1] [, var2 [= valeur2]] [, …, varN [= valeurN]]; Paramètres. var1, var2, …, varN. Le nom de la ou des variables.
https://www.freecodecamp.org › news › var-let-and-const-whats-the-difference
Var, Let, and Const – What's the Difference? - freeCodeCamp.orgvar declarations are globally scoped or function scoped while let and const are block scoped. var variables can be updated and re-declared within its scope; let variables can be updated but not re-declared; const variables can neither be updated nor re-declared.
https://www.w3schools.com › JS › js_let.asp
JavaScript Let - W3SchoolsES6 introduced the two new JavaScript keywords: let and const. These two keywords provided Block Scope in JavaScript: Example. Variables declared inside a { } block cannot be accessed from outside the block: { let x = 2; } // x can NOT be used here. Global Scope. Variables declared with the var always have Global Scope.
https://stackoverflow.com › questions › 22308071
javascript - What is the difference between 'let' and 'const ...The let and const. ES6 let allows you to declare a variable that is limited in scope to the block (Local variable). The main difference is that the scope of a var variable is the entire enclosing function:
https://laconsole.dev › blog › differences-let-var-const-js
Différences entre Let, Var et Const en JavaScript - laConsolelet VS var VS const : tableau comparatif. Choisir entre let, var ou const dépend donc de la portée, des mécaniques de redéclaration et réassignation que vous envisagez pour vos variables. Voici un tableau récapitulant ces caractéristiques.
https://developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Statements › let
let - JavaScript | MDN - MDN Web DocsMany style guides (including MDN's) recommend using const over let whenever a variable is not reassigned in its scope. This makes the intent clear that a variable's type (or value, in the case of a primitive) can never change. Others may prefer let for non-primitives that are mutated.
https://www.freecodecamp.org › news › differences-between-var-let-const-javascript
var, let, and const in JavaScript – the Differences Between These ...Variables declared with const, just like let, are hoisted to the top of their global, local, or block scope – but without a default initialization. var variables, as you've seen earlier, are hoisted with a default value of undefined so they can be accessed before declaration without errors.
https://www.freecodecamp.org › news › understanding-let-const-and-var-keywords
How the let, const, and var Keywords Work in JavaScriptWith ES6 (EcmaScript 2015), the beginning of the modern era in JavaScript, the language got two new keywords to help us declare variables. These are let and const. In this article, we will learn about all of these keywords (yes, including var) with examples, and we'll see when to use them, and when not to use them.
https://www.w3schools.com › js › js_variables.asp
JavaScript Variables - W3SchoolsWhen to Use var, let, or const? 1. Always declare variables. 2. Always use const if the value should not be changed. 3. Always use const if the type should not be changed (Arrays and Objects) 4. Only use let if you can't use const. 5. Only use var if you MUST support old browsers.
