Let and var in javascript
In JavaScript, both the keywords Show
The JavaScript let Vs varHere's the overview of the differences between
JavaScript let Vs var in Local Scopevar is function scopedThe variable declared inside a function with
In the above program, the variable a is declared with let is block-scopedThe variable declared with
Output hello world Uncaught ReferenceError: b is not defined In the above program, the variable a is declared inside the function and it can be accessed anywhere inside the function (a becomes function scoped). However the variable b is declared inside the Hence when you try to access b outside of Note: The variables declared inside a function will be function scoped for both let doesn't allow to redeclare Variables1. A variable declared with
A variable declared with
Output Uncaught SyntaxError: Identifier 'a' has already been declared 2.
Redeclaring a variable with
Redeclaring a variable with
3. When a variable declared with
In the above program, the When a variable declared with let is used in a loop, the value of a variable does not change. For example,
In the above program, let Doesn't Allow HoistingThe variables declared with
The keyword
If you want to learn more about hoisting, visit JavaScript Hoisting. let and var Browser SupportMost of the
modern browsers support the use of To learn more, visit JavaScript let browser support. Note: In case of global scope, both
The variable a will be global scoped and can be accessed anywhere in the program.
The variable a will be global scoped and can be accessed anywhere in the program. What is difference between LET and VAR in Javascript?The main difference between let and var is that scope of a variable defined with let is limited to the block in which it is declared while variable declared with var has the global scope. So we can say that var is rather a keyword which defines a variable globally regardless of block scope.
Should I use VAR or let Javascript?As a general rule, you should always declare variables with const, if you realize that the value of the variable needs to change, go back and change it to let. Use let when you know that the value of a variable will change. Use const for every other variable. Do not use var.
Why is var better than let?let allows you to declare variables that are limited in scope to the block, statement, or expression on which it is used. This is unlike the var keyword, which defines a variable globally, or locally to an entire function regardless of block scope.
What is difference between VAR and let in typescript?The let declarations follow the same syntax as var declarations. Unlike variables declared with var , variables declared with let have a block-scope. This means that the scope of let variables is limited to their containing block, e.g. function, if else block or loop block.
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