JavaScript concept with a cup of coffee and a laptop

Function Scope

If we create a variable within a block of code, it is scoped to that block. This is different than in C#. Code blocks are marked with curly braces ( { } ). So a function has a block of code because it uses curly braces to define it. Let’s look at the previous code sample…

function add( num1, num2 ) {
    let newNum = num1 + num2;
    return newNum;
}
let addSum = add( 1, 2 ); // Variable to hold function call. Allows ease of use.
console.log( newNum ); // Displays ReferenceError: newNum is not defined

Notice that we are trying to access the newNum variable that is in the function block of code…within the curly braces. It is scoped to that block…encapsulated. So it cannot be accessed outside of that block of code.

Happy Coding!

Clay Hess

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