JavaScript “let” and “var” related interview questions
“var” and “let” are the two most frequently used keyword in JavaScript. We use them to declare variables in JavaScript. When we declare a variable using the keyword var
it’s scope becomes the current enclosing execution scope. If the variable is declared inside global scope then it creates a property on the global window object. But when we a variable using the keyword let
then it creates a block scope. If the variable is created in global scope then it does not create a property in global window object.
Following are some interview questions on “let” and “var” keyword:
- Does “let” creates a property in global windown object when declared in global scope?
- What will happen if we have let foo = 1; let foo;
- Does the variable declared with keyword “let” hoisted to top of the block?
- What is temporal dead zone in case of variable declared with keyword “let”
- console.log(foo); let foo = 2; What will happen and why?
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let foo = 1; if (true) { var foo = 2; }
What happens when we execute the above code?
- What is implict global variable
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