10 Most Used JavaScript Methods Every Developer Should Know

Introduction Of JavaScript:

In today’s post we will learn about the 10 Most Used JavaScript Methods Every Developer Should Know. In this I will cover the best 10 methos are mostly used in the website development or any JavaScript developer are used. These new features include several techniques that make routine tasks easier in development processes.

So, let’s start the with the most used ES6 modules:

1.  Map():

               Map() create a new array from calling a function for every array elements. Map() does not execute the function for the empty elements. Map() does not change the original array.

Syntax: array.map(function(currentvalue, index, arr), thisvalue)

Example:

Explanation:

1.      First we can create an array arr with value.

2.      Now create a new array by applying the myArray function to each arr.map(myArray) arr element.

3.      The myArray function then multiplies each element by 10 and returns the result.

4.      The new array adds many more dimensions [20, 30, 40, 60, 80, 90].

5.      console.log(newArr) Prints [20, 30, 40, 60, 80, 90] to the console.

2. filter():

The filter() method creates a shallow copy of the original array, but only the condition is true. Filter() do not create a empty function. Filter() not change the original array.

Syntax: array.filter(function( currentValue, index, arr ), thisvlaue )

Example:

Explanation:

1. This example contains an array of values ​​age.

2. ages.filter(ageFilter) Copies the age filter with the conditions defined in the ageFilter function.

3. The ageFilter() function returns True if age >= 18 or more, well filtering age less than that is Equals to 18 .

4. The filterAge setting contains parameters [18, 20, 19, 24, 34].

5. Set console.log(filterAge) for results [18, 20, 19, 24, 34].

3. reduce():

            The JavaScript Array.reduce() method iterates over the array and applies the reducer function to each element that stores the output value. It takes the initial value and processes the elements from left to right to reduce the array to a single result. This method is very useful for arithmetic operations on arrays such as max, min, and sum.

Syntax: array.reduce(function(total, currentValue, currentIndex, arr), initialValue)

Example:

Explanation:

Let’s Explore the one by one:

1.     arr.reduce() method iterates all the element of the array.

2.     (accumulator, currentValue) => accumulator + currentValue this a callback function.
the accumulator starts from initialVal (Which is 0), and on each iteration, it adds the currentValue in the accumulator.

3.     initialVal provides the 0 value for the accumulator.

4.     The output of this code is 10.

4. find():

            The find() method checks each element of the array and returns the first element that satisfies the given testing function. If any element does not satisfy the testing function, then undefined is returned.

·       If you want the index of the found element, use findindex().

·       If you need the index of a value, use indexOf(). This is similar to findIndex(), except it checks each element by comparing it with the value, not with a testing function.

·       If you need to check if a value is in an array or not, use includes(). This also compares values, not testing functions.

·       If you want to check whether any element satisfies a given testing function, then sum() it.

·       If you want all elements that satisfy the testing function, then filter() it.

Sysntx: array.find(function(currentValue, index, arr),thisValue)

 

Example:

Explanation:

In this example arr is an array with the value.

1.     arr.find((ele) => ele > 12 ): The find() method check the all element in the array and check the element is greater than 12.

2.     When the condition is satisfies the store the value in the arrfind variable.

3.     When we print the variable in console, they give the output 13.

 

5. includes():

            JavaScript includes() method returns true if array content specified value, and false if the value is not found. This method makes it very simple to check the presence or absence of any element in the array. With this you can easily and efficiently get a Boolean result (true/false).

Sysntx: array.includes(element, start)

Example:

Explanation:

In this example we have one array1 variable and their values.

·       array1.includes(3) checks all the elements of the array and returns true if the value is 3.

·      array1.includes(4) checks all the elements of the array and returns false if the value is not 4.

 

6. includes():

            JavaScript String.inclides() method return true if string is present otherwise return false.

NOTE: The include() method is case sensitive means it will treat the uppercase and lowercase characters differently.

Syntax: string.includes(searchvalue, start)

Example:

Explanation:

In this example str is a String value.

·       str.includes(word): This checks whether the word "example" is in the string str or not. In that case, the message would state the 'is in the sentence' else it may state the opposite as 'is not in the sentence'.

·       str.includes(word1): This checks whether the word "Example" (with capital "E") is in the string str or not. Since string matching is case-sensitive, it will return "is not in the sentence".

 
7. Object.keys():

            In Javascript, the Object.keys() function enables forming an array based on the keys of an object. Its return the object key array.

Syntax: Object.keys(object)

Example:

Explanation:

This example uses the Object.keys(obj1) method, which returns all the keys (properties) of the object as an array.

•       obj1 is an object with 3 attributes name, age and gender.

•       Object.keys(obj1) This method places all obj1 keys in an array and returns.

8. Object.entries():

            JavaScript's Object.entries() method turns an object's computable properties into an array. This array contains pairs of [key, value]. This method is very useful when we have to modify or iterate over an object such as an array.

Syntax: Object.values(object)

Example:

Explanation:

This example uses the Object.entries(obj1) method. This method converts each property [key, value] of the obj1 object into a pairwise array.

•       obj1 is an object with 3 attributes: name, age, and gender.

•       Calling Object.entries(obj1) returns an object that is transformed into an array where each property contains all the properties of the [key, value] pair.

9. Arrow Functions (=>):

An arrow function is a short syntax for writing functions in JavaScript. It was introduced in ES6, and writing code using arrow functions becomes more concise and readable, especially when there are small functions.

•       Arrow function is written using => symbol, which makes the code compact.

•       Arrow functions do not have their own context; they inherit this surrounding context.

•       If the function is created from a single expression, then return happens automatically (implicit), which makes the code more concise.

•       Arrow functions do not have arguments object, which is there in regular functions.

Example:        

Explanation:

In this code an arrow function has been created which will print a simple message on the console.

•       const arrowFunction = () => { ... }: This is an arrow function in which no parameters have been given and there is a console.log() statement inside the function which will print a message.

•       arrowFunction(): This line is calling the function which will print "This is the Example of Array Function" on the console.

 

10. Template Literals:

            Template Literal is a new feature in ES6 that gives more control in creating dynamic strings. Previously, strings were created using single quotes (‘) or double quotes (“). But we now create template literals using the backtick (`) character.

Example:

Explanation:

In this code two variable a and b are created:

•       var a is 10 and b is 20.

•       var sum = a + b;: Here a and b are added and their sum is stored in the sum variable.

Then, the sum is printed using template literal in console.log():

Total sum of a and b is ${sum}: In this line the value of sum is being inserted in place of ${sum}. That is, the value of sum which is 30 will be displayed in the output.

Summary:

In this blog we will all 10 method how make javascript better for learning. We will all method with example and detail explanation of the code.