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refactor(curriculum): arrays quiz (#58397)
This commit is contained in:
Jessica Wilkins
@@ -17,45 +17,62 @@ To pass the quiz, you must correctly answer at least 18 of the 20 questions belo
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#### --text--
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What is the correct way to declare a JavaScript array?
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What will be the output for the following code?
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```js
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const numbers = [1, 2, 3];
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console.log(numbers[10]);
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```
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#### --distractors--
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`let arr = array(1, 2, 3);`
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`[1, 2, 3]`
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---
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`let arr = "1, 2, 3"; `
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`null`
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---
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`let arr = {1, 2, 3};`
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`10`
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#### --answer--
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`let arr = [1, 2, 3];`
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`undefined`
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### --question--
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#### --text--
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What is the key difference between primitive and non-primitive data types?
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Which of the following is the correct way access the string `"Jessica"` from the `developers` array?
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#### --distractors--
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Primitives can store multiple values.
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```js
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const developers = ["Jessica", "Naomi", "Tom"];
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developers[1]
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```
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---
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Non-primitives cannot hold references to other objects.
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```js
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const developers = ["Jessica", "Naomi", "Tom"];
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developers[2]
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```
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---
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Non-primitives store values directly.
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```js
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const developers = ["Jessica", "Naomi", "Tom"];
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developers[-1]
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```
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#### --answer--
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Primitives hold direct values, non-primitives hold references.
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```js
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const developers = ["Jessica", "Naomi", "Tom"];
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developers[0]
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```
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### --question--
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@@ -89,6 +106,50 @@ console.log(index);
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#### --text--
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What does the rest syntax do?
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#### --distractors--
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It is used to divide a string into an array of substrings.
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---
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It is used to add or remove elements from any position in an array.
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---
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It is used to add elements to the end of the array and will return the new length.
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#### --answer--
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It captures the remaining elements of an array into a new array.
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### --question--
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#### --text--
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What is array destructuring?
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#### --distractors--
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It is used to concatenate all of the elements of an array into a single string.
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---
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It is used to check if an array contains a specific value.
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---
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It is used to remove the last element from an array and will return that removed element.
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#### --answer--
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It is used to extract values from arrays and assign them to variables in a more concise and readable way.
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### --question--
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#### --text--
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What value will be assigned to the `arr2` variable?
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```js
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@@ -117,29 +178,29 @@ console.log(arr2);
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#### --text--
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What will this code print to the console?
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What will this code log 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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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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`['red', 'purple', 'green', 'yellow']`
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`["red", "blue", "green", "yellow"]`
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---
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`['red', 'blue', 'yellow']`
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`["red", "blue", "yellow"]`
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---
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`['red', 'blue', 'green', 'yellow']`
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`["red", "yellow"]`
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#### --answer--
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`['red', 'purple', 'yellow']`
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`["red", "purple", "yellow"]`
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### --question--
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@@ -148,26 +209,26 @@ console.log(colors);
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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 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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`['apple', 'banana']`
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`["apple", "banana"]`
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---
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`['cherry', 'date']`
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`["cherry", "date"]`
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---
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`['apple', 'cherry']`
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`["apple", "cherry"]`
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#### --answer--
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`['banana', 'cherry']`
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`["banana", "cherry"]`
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### --question--
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@@ -177,15 +238,15 @@ Which method returns the first index of a given element in an array?
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#### --distractors--
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`findIndex()`
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`firstIndex()`
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---
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`lastIndexOf()`
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`lastIndex()`
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---
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`slice()`
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`searchIndex()`
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#### --answer--
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@@ -195,7 +256,7 @@ Which method returns the first index of a given element in an array?
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#### --text--
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Which method removes the first element from an array and shifts all other elements down?
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Which method is used to remove the first element from an array and returns that removed element?
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#### --distractors--
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@@ -217,7 +278,7 @@ Which method removes the first element from an array and shifts all other elemen
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#### --text--
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What does `Array.prototype.concat()` do?
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What does the `concat()` method do?
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#### --distractors--
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@@ -239,166 +300,97 @@ Merges two arrays into a new array.
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#### --text--
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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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It throws a syntax error.
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---
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The extra space is filled with `undefined`.
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---
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Nothing happens; the array remains the same size.
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#### --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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What will be the output of this code ?
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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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const fruits = ["apple", "banana", "cherry", "apple", "orange"];
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fruits.splice(0, 1);
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console.log(fruits);
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```
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#### --distractors--
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`['banana', 'cherry', 'orange']`
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`["apple", "banana", "cherry", "apple", "orange"]`
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---
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`['apple', 'cherry', 'apple', 'orange']`
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`["apple", "banana", "cherry"]`
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---
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`['banana', 'cherry', 'apple']`
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`["cherry", 'apple']`
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#### --answer--
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`['banana', 'cherry', 'apple', 'orange']`
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`["banana", "cherry", "apple", "orange"]`
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### --question--
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#### --text--
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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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What does the `includes()` method do?
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#### --distractors--
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`false`
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It is used to divide a string into an array of substrings.
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---
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`[1, 2, 3, 4, 5]`
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It is used to concatenate all of the elements of an array into a single string.
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---
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`undefined`
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It is used to add or remove elements from any position in an array.
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#### --answer--
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`true`
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It is used to check if an array contains a specific value.
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### --question--
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#### --text--
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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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Which of the following methods is used to reverse an array in place?
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#### --distractors--
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`false`
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`reversed()`
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---
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`[2, 4, 6, 8]`
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`reverseArr()`
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---
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`Error`
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`reversing()`
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#### --answer--
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`true`
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`reverse()`
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### --question--
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#### --text--
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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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What is a two dimensional array?
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#### --distractors--
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`[[1, 2, 3], [4, 5, 6]]`
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An array that only contains object literals.
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---
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`[[1, 2], [4, 5], [7, 8]]`
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An array of fixed length.
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---
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`[[7, 8, 9]]`
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An array of floating point numbers.
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#### --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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Which of the following statements about `.length` is correct?
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#### --distractors--
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It counts the number of values in a 2D array.
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---
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It returns `undefined` for empty arrays.
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---
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It gives the total number of elements in a 2D array.
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#### --answer--
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It counts the number of top-level elements in a 2D array.
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An array of arrays.
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### --question--
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@@ -426,75 +418,73 @@ It returns `-1` if the element is not found.
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#### --text--
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What is the main difference between `push()` and `concat()` when working with arrays?
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Which of the following is NOT an array method?
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#### --distractors--
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`push()` adds multiple arrays together, while `concat()` adds a single element.
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`includes()`
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---
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`concat()` modifies the original array, while `push()` creates a new array.
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`pop()`
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---
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Both `push()` and `concat()` are immutable methods.
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`push()`
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#### --answer--
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`push()` modifies the original array, while `concat()` creates a new array.
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`keys()`
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### --question--
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#### --text--
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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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It is used to add extra elements to the array.
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---
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It allows you to access elements outside the array's bounds.
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---
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It removes the last element of the array.
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#### --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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What will be the result of this code ?
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What will be the output for the following 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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const arr = ["o", "l", "l", "e", "h"];
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console.log(arr.join(""));
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```
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#### --distractors--
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2
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`["o", "l", "l", "e", "h"]`
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---
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5
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`"hello"`
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---
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4
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`undefined`
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#### --answer--
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3
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`"olleh"`
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### --question--
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#### --text--
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What will be the result of using the `shift()` method on an empty array?
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#### --distractors--
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`TypeError`
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---
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`[]`
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---
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`null`
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#### --answer--
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`undefined`
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### --question--
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@@ -504,7 +494,7 @@ Which method will return a new array without changing the original array?
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#### --distractors--
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`splice()`
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`shift()`
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---
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Reference in New Issue
Block a user