- 3 Should I use VAR or let in node JS?
- 5 What’s the difference between VAR and let Swift?
- 8 Is Let hoisted?
- 10 Should you use VAR or let?
- 11 Is const better than let?
- 12 Is const faster than let?
- 13 Why you should stop using var?
let allows you to declare variables that are limited to the scope of a block statement, or expression on which it is used, unlike the var keyword, which declares a variable globally, or locally to an entire function regardless of block scope.
Should I use VAR or let in node JS?
The main difference is the scope difference, while let can be only available inside the scope it’s declared, like in for loop, var can be accessed outside the loop for example.
What’s the difference between VAR and let Swift?
Both let and var are for creating variables in Swift. let helps you create immutable variables (constants) while on the other hand var creates mutable variables. The difference between them is that when you create a constant using let you have to assign something to it before the first use and can’t reassign it.
What are infinite loops? An infinite loop is a piece of code that keeps running forever as the terminating condition is never reached. An infinite loop can crash your program or browser and freeze your computer.
Is Let hoisted?
Let and const hoisting Variables declared with let and const are also hoisted, but unlike for var the variables are not initialized with a default value of undefined. Until the line in which they are initialized is executed, any code that accesses these variables will throw an exception.
Should you use VAR or let?
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.
Is const better than let?
Turns out, const is almost exactly the same as let. However, the only difference is that once you’ve assigned a value to a variable using const, you can’t reassign it to a new value. The take away above is that variables declared with let can be re-assigned, but variables declared with const can’t be.
Is const faster than let?
It appears that using const would inherently make code a little faster, because it seems to reduce the amount of hoisting necessary. Take the following, basic example: While it appears trivial, if let and const are actually faster, then that would be a strong argument for consistently using them.
Why you should stop using var?
Closures. This one’s hard to understand if it’s a new concept, but a closure is a function that references a free variable. When we have a closure with a var variable, the reference is remembered, which can be troublesome when inside a loop where that variable changes.
When you use var, you are instantiating a variable in the current scope. This will also prevent access of variables named the same in higher scope, within the current scope.