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JavaScript JavaScript Functions Pass Information Into Functions Variable Scope

Stephen Cole
Stephen Cole
Courses Plus Student 15,549 Points

Does creating a parameter define the scope of a variable?

If I create a function with a parameter, does that force the scope to be local?

let person = 'Lee';

function greeting(person) {
  person = 'Meg';
  alert(`Hi, ${person};

A quick test shows that it is local and does NOT change the global variable. However, is that really what is happening or is there other magic behind the scenes?

1 Answer

Steven Parker
Steven Parker
218,636 Points

Giving a parameter or new function variable the same name as a variable in the outer scope makes it not possible to access the outer variable. This is known as "shadowing".

If this isn't desired, the only reliable remedy is to give the variables and parameters unique names.