Js Arrays Flashcards
What is the syntax to create an array in JavaScript?
let array = []; or let array = new Array();
True or False: Arrays in JavaScript can hold elements of different data types.
True
What method would you use to add an element to the end of an array?
array.push(element)
What method removes the last element from an array?
array.pop()
Fill in the blank: The length of an array can be found using the property ____.
length
What method is used to combine two or more arrays?
array.concat()
Which loop is often used to iterate over arrays in JavaScript?
for loop
True or False: The forEach() method can be used to iterate over an array.
True
What is the difference between a for loop and a forEach loop?
A for loop requires manual index management, while forEach automatically handles iteration.
What does the map() method do in JavaScript?
It creates a new array populated with the results of calling a provided function on every element in the calling array.
How do you access the first element of an array named ‘myArray’?
myArray[0]
What is the output of console.log([1, 2, 3].length)?
3
Fill in the blank: The ____ method creates a new array with all elements that pass the test implemented by the provided function.
filter
What type of loop is the ‘for…of’ loop?
It is used to iterate over iterable objects like arrays.
True or False: The indexOf() method returns the first index at which a given element can be found in the array.
True
What does the reduce() method do?
It executes a reducer function on each element of the array, resulting in a single output value.
What is the syntax for a traditional for loop?
for (let i = 0; i < array.length; i++) { }
What is the purpose of the splice() method?
It changes the contents of an array by removing or replacing existing elements and/or adding new elements.
How do you create a copy of an array?
You can use array.slice() or the spread operator […array].
What is the output of console.log([1, 2, 3].includes(2))?
True
Fill in the blank: The ____ method reverses the elements of an array in place.
reverse
What is the result of using the shift() method on an array?
It removes the first element from the array and returns that removed element.
What is the primary use of the forEach() method?
To execute a provided function once for each array element.
True or False: Arrays in JavaScript are immutable.
False
What method would you use to find the index of an element in an array?
array.indexOf(element)
