Quick JavaScript Crash Course - Modern and Advanced JavaScript - Let Const Rather than Var

The lecture discusses the issues with the 'WAR' keyword and introduces 'let' and 'construction' as replacements. 'Let' is used for block-scoped variables, ensuring correct behavior in loops. 'Construction' is used for constants, preventing reassignment. The lecture also covers the limitations of 'const' in protecting object references and suggests using the 'freeze' method for deeper protection. Best practices recommend using 'let' for variables that change and 'const' for constants.

What is a key advantage of using 'let' over 'var' in loops?

• It creates a new variable for each iteration.

• It allows variable hoisting.

• It is globally scoped.

• It is function-scoped.

What happens if you try to redefine a variable declared with 'let' in the same scope?

• The variable is redefined without error.

• The variable is ignored.

• An error is thrown.

• The variable is hoisted.

What is the primary purpose of using 'const' in JavaScript?

• To allow variable hoisting.

• To define a constant that cannot be reassigned.

• To create a globally scoped variable.

• To enable function scoping.

How does 'const' handle objects in JavaScript?

• It makes the object globally accessible.

• It allows changes to the object but not to the reference.

• It prevents any changes to the object.

• It allows the object to be redefined.

What method can be used to prevent modifications to an object in JavaScript?

• Object.seal()

• Object.lock()

• Object.freeze()

• Object.prevent()

What is a limitation of using Object.freeze() on an object?

• It only performs a shallow freeze.

• It can only be used on primitive data types.

• It does not work on arrays.

• It makes the object immutable.

When should you use 'let' instead of 'const'?

• When the variable is globally scoped.

• When the variable is function-scoped.

• When the variable is a constant.

• When the variable value will change.