17, Jan 2023
How to solve the “TypeError: array.splice is not a function” when ‘var array = {}’?

The splice()
method is used to add or remove elements from an array. It is not a method that is available on objects.
If you get the error “TypeError: array.splice is not a function”, it means that you are trying to call the splice()
method on an object that is not an array.
let array = {};
array.splice(0, 1); // TypeError: array.splice is not a function
To solve this error, you will need to make sure that you are calling the splice()
method on an array, not on an object.
For example:
let array = [1, 2, 3];
array.splice(0, 1); // [1]
console.log(array); // [2, 3]
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17, Jan 2023
How do I check if an array includes a value in JavaScript?

In JavaScript, you can use the Array.prototype.includes()
method to check if an array includes a specific value.
Here’s an example of how you can use the includes()
method to check if an array of numbers includes the number 42:
var numbers = [1, 2, 3, 42, 5];
console.log(numbers.includes(42)); // output: true
The includes()
method returns a boolean value indicating whether the specified value is found in the array. In the above example, since 42 is present in the array the output is true
.
You can also check if the array includes an object in the array
var people = [{name:'John',age:40}, {name:'Mike',age:25}, {name:'Bob',age:35}];
console.log(people.includes({name:'Bob',age:35})); // output: false
It will return false
because it compares object reference not the object values.
In this case, you can use Array.prototype.find() method to find the desired object by key-value match
console.log(people.find(person => person.name === 'Bob' && person.age === 35));
This method returns the first element in the array that satisfies the provided testing function; otherwise, undefined is returned.
You can also use indexOf()
method to check if a value exists in an array or not.
console.log(people.indexOf({name:'Bob',age:35}) != -1)
It returns the first index at which a given element can be found in the array, or -1 if it is not present.
17, Jan 2023
How can I remove a specific item from an array?

There are a few ways to remove a specific item from an array in JavaScript. Here are a few methods that you can use:
- The
Array.prototype.splice()
method can be used to remove an item from an array by specifying the index of the item and the number of items to remove. Here is an example of how you can usesplice()
to remove the item at index 2 from an array:
var numbers = [1, 2, 3, 4, 5];
numbers.splice(2, 1);
console.log(numbers); // output: [1, 2, 4, 5]
- The
Array.prototype.filter()
method can be used to create a new array with all elements that pass the test implemented by the provided function. Here’s an example of how you can use filter to remove a specific number from an array:
var numbers = [1, 2, 3, 4, 5];
numbers = numbers.filter(function(num) { return num !== 3 });
console.log(numbers); // output: [1, 2, 4, 5]
- You can use
Array.prototype.indexOf()
method to find the index of the desired item and then useArray.prototype.slice()
to remove that element.
var numbers = [1, 2, 3, 4, 5];
var index = numbers.indexOf(3);
if (index > -1) {
numbers = numbers.slice(0, index).concat(numbers.slice(index + 1));
}
console.log(numbers); // output: [1, 2, 4, 5]
- You can also use the
Array.prototype.findIndex()
to find the index of the item andArray.prototype.splice()
to remove the specific item.
var numbers = [1, 2, 3, 4, 5];
var index = numbers.findIndex(num => num === 3);
if (index !== -1) numbers.splice(index, 1);
console.log(numbers); // output: [1, 2, 4, 5]
All of the above methods will remove the specific item from the array, and return the modified array.
It’s important to note that the splice()
method modifies the original array, while filter and slice returns new array.
Also, if you are trying to remove multiple elements from an array, you can use these methods multiple times or use nested looping to remove those elements.
17, Jan 2023
How to insert an item into an array at a specific index

In JavaScript, you can use the Array.prototype.splice()
method to insert an item into an array at a specific index.
The splice()
method takes three arguments: the index at which to start changing the array (this is where you want to insert the item), the number of items to remove (this should be 0 when you’re inserting an item), and the item(s) to insert.
Here’s an example of how you can use the splice()
method to insert the number 42 at index 2 of an array:
var numbers = [1, 2, 3, 4, 5];
numbers.splice(2, 0, 42);
console.log(numbers); // output: [1, 2, 42, 3, 4, 5]
You can also insert multiple items at once by passing more than one item as the third argument to the splice()
method:
var numbers = [1, 2, 3, 4, 5];
numbers.splice(2, 0, 42, 43, 44);
console.log(numbers); // output: [1, 2, 42, 43, 44, 3, 4, 5]
It’s important to note that the splice()
method modifies the original array, so after you call the splice()
method, the item(s) will be inserted at the specified index and the remaining elements will be shifted to the right.
You can also use spread operator to insert an item into array at a specific index
let numbers = [1, 2, 3, 4, 5];
let index = 2;
numbers = [...numbers.slice(0, index), 42, ...numbers.slice(index)];
console.log(numbers); // output: [1, 2, 42, 3, 4, 5]
It will return a new array with the element added to the specified index.
In both case, Keep in mind that if the index passed to the splice method is greater than the length of the array, the new element(s) will be added to the end of the array.
11, Jan 2023
How can I remove an array element by index,using javaScript?

In JavaScript, you can use the Array.prototype.splice()
method to remove an element from an array by specifying the index of the element and the number of elements to remove.
Here’s an example of how you can use the splice()
method to remove the element at index 2 from an array:
var numbers = [1, 2, 3, 4, 5];
numbers.splice(2, 1);
console.log(numbers); // output: [1, 2, 4, 5]
The first argument passed to the splice()
method is the index of the element to remove and the second argument is the number of elements to remove. In the above example, we are removing 1 element starting from the index 2.
You can also remove more than one element by passing a higher number as the second argument to the splice()
method:
var numbers = [1, 2, 3, 4, 5,6,7,8];
numbers.splice(2, 3);
console.log(numbers); // output: [1, 2, 7, 8]
Here we are removing 3 element starting from the index 2.
It’s important to note that the splice()
method modifies the original array, so after you call the splice()
method, the element at the specified index will be removed and the remaining elements will be shifted to the left.
You can also use spread operator with slice()
method to remove an array element by index.
let numbers = [1, 2, 3, 4, 5];
let index = 2;
numbers = [...numbers.slice(0,index), ...numbers.slice(index + 1)];
console.log(numbers); // output: [1, 2, 4, 5]
It will return new array without the element in the specified index.
Also be careful when removing elements from an array if you are working with loops, as it can cause the loop to skip some elements or lead to unexpected behavior.
9, Jan 2023
How can I add new array elements at the beginning of an array in JavaScript?

There are several ways to add new elements to the beginning of an array in JavaScript. Here are a few options:
- Use the
unshift()
method:
let array = [1, 2, 3];
array.unshift(0);
console.log(array); // [0, 1, 2, 3]
- Use the
splice()
method:
let array = [1, 2, 3];
array.splice(0, 0, 0);
console.log(array); // [0, 1, 2, 3]
- Use the spread operator (
...
) and theconcat()
method:
let array = [1, 2, 3]; let newArray = [0].concat(array); console.log(newArray); // [0, 1, 2, 3] // or let newArray = [0, ...array]; console.log(newArray); // [0, 1, 2, 3]



