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feat(curriculum): add the JavaScript Array Quiz (#56493)
This commit is contained in:
Ritesh S Hiremath
committed by
GitHub
GitHub
parent
3fde9b45a9
commit
ed5fb9bca8
@@ -17,439 +17,503 @@ Answer all of the questions below correctly to pass the quiz.
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#### --text--
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Placeholder question
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What is the correct way to declare a JavaScript array?
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#### --distractors--
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Placeholder distractor 1
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`let arr = array(1, 2, 3);`
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---
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Placeholder distractor 2
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`let arr = "1, 2, 3"; `
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---
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Placeholder distractor 3
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`let arr = {1, 2, 3};`
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#### --answer--
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Placeholder answer
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`let arr = [1, 2, 3];`
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### --question--
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#### --text--
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Placeholder question
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What is the key difference between primitive and non-primitive data types?
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#### --distractors--
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Placeholder distractor 1
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Primitives can store multiple values.
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---
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Placeholder distractor 2
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Non-primitives cannot hold references to other objects.
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---
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Placeholder distractor 3
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Non-primitives store values directly.
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#### --answer--
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Placeholder answer
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Primitives hold direct values, non-primitives hold references.
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### --question--
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#### --text--
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Placeholder question
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What value will be assigned to the `index` variable?
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```js
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const numbers = [10, 20, 30, 40];
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const index = numbers.indexOf(20);
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console.log(index);
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```
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#### --distractors--
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Placeholder distractor 1
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2
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---
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Placeholder distractor 2
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3
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---
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Placeholder distractor 3
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-1
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#### --answer--
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Placeholder answer
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1
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### --question--
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#### --text--
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Placeholder question
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What value will be assigned to the `arr2` variable?
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```js
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const arr1 = [1, 2, 3];
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const arr2 = [...arr1, 4, 5];
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console.log(arr2);
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```
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#### --distractors--
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Placeholder distractor 1
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`[4, 5, 1, 2, 3]`
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---
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Placeholder distractor 2
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`[1, 2, [3, 4, 5]]`
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---
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Placeholder distractor 3
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`[1, 2, 3]`
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#### --answer--
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Placeholder answer
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`[1, 2, 3, 4, 5]`
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### --question--
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#### --text--
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Placeholder question
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What will this code print to the console?
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```js
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const colors = ['red', 'blue', 'green', 'yellow'];
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colors.splice(1, 2, 'purple');
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console.log(colors);
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```
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#### --distractors--
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Placeholder distractor 1
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`['red', 'purple', 'green', 'yellow']`
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---
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Placeholder distractor 2
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`['red', 'blue', 'yellow']`
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---
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Placeholder distractor 3
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`['red', 'blue', 'green', 'yellow']`
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#### --answer--
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Placeholder answer
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`['red', 'purple', 'yellow']`
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### --question--
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#### --text--
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Placeholder question
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What value will be assigned to the `slicedArr` variable?
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```js
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const arr = ['apple', 'banana', 'cherry', 'date'];
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const slicedArr = arr.slice(1, 3);
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console.log(slicedArr);
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```
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#### --distractors--
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Placeholder distractor 1
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`['apple', 'banana']`
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---
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Placeholder distractor 2
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`['cherry', 'date']`
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---
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Placeholder distractor 3
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`['apple', 'cherry']`
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#### --answer--
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Placeholder answer
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`['banana', 'cherry']`
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### --question--
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#### --text--
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Placeholder question
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Which method returns the first index of a given element in an array?
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#### --distractors--
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Placeholder distractor 1
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`findIndex()`
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---
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Placeholder distractor 2
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`lastIndexOf()`
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---
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Placeholder distractor 3
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`slice()`
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#### --answer--
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Placeholder answer
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`indexOf()`
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### --question--
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#### --text--
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Placeholder question
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Which method removes the first element from an array and shifts all other elements down?
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#### --distractors--
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Placeholder distractor 1
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`pop()`
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---
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Placeholder distractor 2
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`slice()`
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---
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Placeholder distractor 3
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`splice()`
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#### --answer--
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Placeholder answer
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`shift()`
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### --question--
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#### --text--
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Placeholder question
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What does `Array.prototype.concat()` do?
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#### --distractors--
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Placeholder distractor 1
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Joins array elements into a string.
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---
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Placeholder distractor 2
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Adds an element to the beginning of an array.
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---
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Placeholder distractor 3
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Removes an element from the array.
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#### --answer--
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Placeholder answer
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Merges two arrays into a new array.
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### --question--
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#### --text--
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Placeholder question
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What happens if you set an array's length to a value smaller than the current length?
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#### --distractors--
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Placeholder distractor 1
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It throws a syntax error.
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---
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Placeholder distractor 2
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The extra space is filled with `undefined`.
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---
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Placeholder distractor 3
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Nothing happens; the array remains the same size.
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#### --answer--
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Placeholder answer
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The array gets truncated, removing elements beyond the new length.
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### --question--
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#### --text--
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Placeholder question
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What will be the output of this code ?
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```js
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const fruits = ['apple', 'banana', 'cherry', 'apple', 'orange'];
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const index = fruits.indexOf('apple');
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if (index !== -1) {
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fruits.splice(index, 1);
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}
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console.log(fruits);
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```
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#### --distractors--
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Placeholder distractor 1
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`['banana', 'cherry', 'orange']`
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---
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Placeholder distractor 2
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`['apple', 'cherry', 'apple', 'orange']`
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---
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Placeholder distractor 3
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`['banana', 'cherry', 'apple']`
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#### --answer--
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Placeholder answer
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`['banana', 'cherry', 'apple', 'orange']`
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### --question--
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#### --text--
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Placeholder question
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What is the final value of `result` in the following code?
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```js
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const arr1 = [1, 2];
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const arr2 = [3, 4, 5];
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const combined = arr1.concat(arr2);
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const result = combined.includes(3);
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console.log(result);
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```
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#### --distractors--
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Placeholder distractor 1
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`false`
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---
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Placeholder distractor 2
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`[1, 2, 3, 4, 5]`
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---
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Placeholder distractor 3
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`undefined`
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#### --answer--
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Placeholder answer
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`true`
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### --question--
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#### --text--
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Placeholder question
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What does the following code output?
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```js
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const nums = [1, 2, 3, 4];
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const doubled = nums.map(n => n * 2);
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console.log(doubled.includes(8));
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```
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#### --distractors--
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Placeholder distractor 1
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`false`
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---
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Placeholder distractor 2
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`[2, 4, 6, 8]`
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---
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Placeholder distractor 3
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`Error`
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#### --answer--
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Placeholder answer
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`true`
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### --question--
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#### --text--
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Placeholder question
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What is the output when using `splice()` to remove elements from a 2D array?
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```js
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let matrix = [
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[1, 2, 3],
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[4, 5, 6],
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[7, 8, 9]
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];
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matrix.splice(1, 1);
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console.log(matrix);
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```
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#### --distractors--
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Placeholder distractor 1
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`[[1, 2, 3], [4, 5, 6]]`
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---
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Placeholder distractor 2
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`[[1, 2], [4, 5], [7, 8]]`
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---
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Placeholder distractor 3
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`[[7, 8, 9]]`
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#### --answer--
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Placeholder answer
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`[[1, 2, 3], [7, 8, 9]]`
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### --question--
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#### --text--
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Placeholder question
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Which of the following statements about `.length` is correct?
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#### --distractors--
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Placeholder distractor 1
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It counts the number of values in a 2D array.
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---
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Placeholder distractor 2
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It returns `undefined` for empty arrays.
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---
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Placeholder distractor 3
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It gives the total number of elements in a 2D array.
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#### --answer--
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Placeholder answer
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It counts the number of top-level elements in a 2D array.
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### --question--
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#### --text--
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Placeholder question
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Which of the following is true about the `indexOf()` method in arrays?
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#### --distractors--
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Placeholder distractor 1
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It always returns the last occurrence of the element.
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---
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Placeholder distractor 2
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It throws an error if the element is not found.
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---
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Placeholder distractor 3
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It requires the array to be sorted.
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#### --answer--
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Placeholder answer
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It returns `-1` if the element is not found.
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### --question--
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#### --text--
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Placeholder question
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What is the main difference between `push()` and `concat()` when working with arrays?
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#### --distractors--
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Placeholder distractor 1
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`push()` adds multiple arrays together, while `concat()` adds a single element.
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---
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Placeholder distractor 2
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`concat()` modifies the original array, while `push()` creates a new array.
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---
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Placeholder distractor 3
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Both `push()` and `concat()` are immutable methods.
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#### --answer--
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Placeholder answer
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`push()` modifies the original array, while `concat()` creates a new array.
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### --question--
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#### --text--
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Placeholder question
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How does the rest parameter `...rest` work in array destructuring in JavaScript?
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#### --distractors--
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Placeholder distractor 1
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It is used to add extra elements to the array.
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---
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Placeholder distractor 2
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It allows you to access elements outside the array's bounds.
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---
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Placeholder distractor 3
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It removes the last element of the array.
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#### --answer--
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Placeholder answer
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It collects the remaining elements into a new array after the initial elements are assigned to variables.
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### --question--
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#### --text--
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Placeholder question
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What will be the result of this code ?
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```js
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const numbers = [10, 20, 30];
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numbers.push(40);
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numbers.pop();
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const length = numbers.length;
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console.log(length);
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```
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#### --distractors--
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Placeholder distractor 1
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2
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---
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Placeholder distractor 2
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5
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---
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Placeholder distractor 3
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4
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#### --answer--
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Placeholder answer
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3
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### --question--
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#### --text--
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Placeholder question
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Which method will return a new array without changing the original array?
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#### --distractors--
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Placeholder distractor 1
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`splice()`
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---
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Placeholder distractor 2
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`pop()`
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---
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Placeholder distractor 3
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`push()`
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#### --answer--
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Placeholder answer
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`slice()`
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Reference in New Issue
Block a user