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Questions and Answers
In JavaScript, what is hoisting?
What happens if there is a mismatch between the argument list and parameter list in JavaScript functions?
What happens to variables and functions declared with let or const in JavaScript's hoisting behavior?
What is the purpose of the arguments object in JavaScript functions?
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What is the correct way to access values passed to a JavaScript function using an array?
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What does JavaScript do with variables and function declarations by default?
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In JavaScript, how are arrays created using the 'new Array' method?
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What is the index of the last element in a JavaScript array of length n?
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How can you create a literal array in JavaScript?
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What happens when you modify the length property of a JavaScript array at runtime?
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What is the correct syntax for defining a function in JavaScript?
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What type of index does the 'for-in' loop in JavaScript return when used with an array?
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Study Notes
Hoisting in JavaScript
- Hoisting is a behavior in JavaScript where variables and functions are moved to the top of their scope, regardless of their placement in the code.
Function Arguments and Parameters
- A mismatch between the argument list and parameter list in JavaScript functions does not cause an error; instead, excess arguments are ignored, and excess parameters are set to
undefined.
Let and Const in Hoisting
- Variables and functions declared with
letorconstare not hoisted, unlike those declared withvar; instead, they are placed in a "temporal dead zone" until they are declared.
The Arguments Object
- The
argumentsobject in JavaScript functions is an array-like object that contains the values passed to the function.
Accessing Function Arguments
- To access values passed to a JavaScript function using an array, you can use the
argumentsobject or the rest parameter syntax (...args).
Default Behavior
- By default, JavaScript moves variables and function declarations to the top of their scope, but this can be overridden by using
letorconst.
Creating Arrays
- Arrays can be created using the
new Arraymethod, but this is not recommended; instead, use the literal array syntax ([]). - Arrays can also be created using the literal array syntax, where each element is separated by a comma.
Array Index
- The index of the last element in a JavaScript array of length
nisn - 1.
Modifying Array Length
- When you modify the
lengthproperty of a JavaScript array at runtime, elements are added or removed from the end of the array accordingly.
Defining Functions
- The correct syntax for defining a function in JavaScript is
function name(parameters) { code }orconst name = function(parameters) { code }.
For-In Loop
- The
for-inloop in JavaScript returns a string index when used with an array, not a numeric index.
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Description
Test your knowledge of JavaScript arrays and functions with this quiz. Learn about creating arrays, indexing elements, using the new Array method, and creating literal arrays with square brackets.
