JavaScript Code Snippets

Pushpendra Shukla
Oct 26, 2023

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Introduction

Use our in-depth guide to explore the potential of JavaScript code snippets. This article is brimming with helpful hints, techniques, and best practices that will enable developers of all skill levels to maximize the potential of JavaScript code snippets. Learn how to use snippets efficiently in your projects, increase your productivity, and unlock the power of reusable code. This manual will provide you with the tools you need to understand JavaScript code snippets and advance your coding abilities. It includes time-saving shortcuts and creative strategies.

What is Code Snippets?

Trim, reusable chunks of code known as "code snippets" are used in programming to quickly complete particular tasks or develop frequently used features. By offering pre-written code blocks that can be quickly integrated into their projects, they assist developers in saving time and effort by eliminating the need to continually write the same code from scratch. To speed up the coding process and encourage code reuse, code snippets are commonly used in various programming languages and integrated development environments (IDEs).

Why are Code Snippets used?

There are various objectives for using code snippets.

Time Savings: They save the need to manually write the same code by offering pre-written code that can be rapidly placed into a project.
Productivity: Code snippets simplify the coding process, allowing developers to work more efficiently and concentrate on addressing complex issues.
Code Reusability: By employing snippets, developers may create reusable sections of code, cutting down on duplication and fostering good coding practices.

Snippets guarantee that specific coding patterns or best practices are used consistently throughout a project.

Snippets can contain complex logic, simplifying usage and maintenance of complex code.

Learning & Education: Novice programmers might pick up knowledge from carefully written snippets by observing how specific functionality is implemented.
Error Avoidance: Since snippets are frequently tested and validated, they can assist in avoiding typical errors and defects.
Standardization: Teams can generate and distribute standardized code snippets to maintain uniformity and collaboration.
Quick Prototyping: Snippets make experimentation and quick prototyping possible.

Snippets can be utilized in a variety of settings and platforms, improving cross-platform compatibility.

How to use Code Snippets

The usefulness, usability, and effect on code productivity and efficiency of the top 25 JavaScript snippets are demonstrated in this article. The activities covered by these snippets include handling DOM components, doing simple computations, manipulating arrays and objects, and more.

1. Checking if a Variable is Defined

Example

function ExampleOne()
	{
		const isDefined = (variable) => typeof variable !== 'undefined';
		let x;
		let y = 5;
		console.log("Value of x : ", isDefined(x)); // Output: false
		console.log("Value of y : ",isDefined(y)); // Output: true
		var example1Element = document.getElementById("responseexampleone");
		example1Element.innerHTML = "Value of x : " + x + "<br/> Value of y : " + y;
		if (typeof x === 'undefined') {
  			// This condition will be true
		}
	}

This function is a concise and reliable way to perform the check. It is a common approach used in many JavaScript projects. Choose the method that best fits your specific use case. Generally, using a type of or strict equality check with undefined is the safer option to check if a variable is defined.

2. Generating a Random Number within a Range

Example

const getRandomNumber = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min;
			const min = 10;
			const max = 20;
			const randomNumber = Math.random() * (max - min) + min;
			console.log(randomNumber); // Output will be a random number between 10 (inclusive) and 20 (exclusive).

Keep in mind that the min value is inclusive, and the max value is exclusive. This means the function will return a number greater than or equal to min but less than max. If you need the random number to be an integer, you can use Math. floor, Math. ceil, or Math. round functions to round the result. For example, using Math. floor will give you an integer that is less than or equal to the highest number in the range:

3. Checking if an Element Exists in an Array

One way to check if an element exists in an array is to use the indexOf() method. This method returns the index of the first occurrence of the element in the array, or -1, if the element is not found.

Example

var fruits = ["apple", "banana", "orange", "mango"];
var index = fruits.indexOf("banana");
if (index != -1) {
console.log("banana is in the array at index " + index);
} else {
console.log("banana is not in the array");
}

This code will print the banana in the array at index 1 to the console. The indexOf() method can be used with different types of arrays, such as numbers, strings, or objects. However, it only checks for strict equality, meaning that the element must match exactly with the array element. For example, if you have an array of objects, you cannot use indexOf() to check for an object with the same properties but a different reference. You would need to use a different method, such as findIndex() or some(), to check for such cases.

4. Deep Cloning an Object

One way to deep-clone an object in JavaScript is to use the JSON.parse() and JSON.stringify() methods. These methods convert an object to a JSON string and then parse it back to a new object.

Example

var obj = {
name: "John",
age: 25,
address: {
city: "New York",
country: "USA"
}
};
var clone = JSON.parse(JSON.stringify(obj));
clone.name = "Jane";
clone.address.city = "London";
clone.address.country = "UK";
console.log(obj); // { name: 'John', age: 25, address: { city: 'New York', country: 'USA' } }
console.log(clone); // { name: 'Jane', age: 25, address: { city: 'London', country: 'UK' } }

This code will create a deep copy of the obj object and store it in the clone variable. Then, it will modify some properties of the clone object and compare it with the original object. The console will show that the original and the clone objects are different, meaning that they are not referencing the same object in memory.

5. Converting an Array to an Object

One way to convert an array to an object in JavaScript is to use the Object. assign() method. This method copies all enumerable properties from one or more source objects to a target object.

Example

var arr = [1, 2, 3, 4, 5];
var obj = Object.assign({}, arr);
console.log(typeof obj); // "object"
console.log(obj); // { '0': 1, '1': 2, '2': 3, '3': 4, '4': 5 }

This code will create an object with the same values as the array but with the array indices as the property names. The Object. assign() method can be used with different types of arrays, such as strings, booleans, or objects.

6. Get the Current Date and Time

const currentDate = new Date(); console.log(currentDate);

This snippet retrieves the current date and time, which can be helpful for various tasks such as displaying timestamps or scheduling events.

7. Check if an Object Contains a Property

Example

const person = { name: "John", age: 30, city: "New York", };
const hasAgeProperty = "age" in person;
console.log("Has age property:", hasAgeProperty);

By using the in operator, this snippet checks if an object contains a specific property.

8. Get the Current URL

Example

const currentURL = window.location.href;
console.log(currentURL);

This snippet retrieves the current URL, which is useful for implementing share buttons or handling navigation.

9. Truncate a String

Example

function truncateString(str, maxLength)
{
    return str.length > maxLength ? str.slice(0, maxLength) + "..." : str;
}
const longString = "Lorem ipsum dolor sit amet, consectetur adipiscing elit.";
const truncatedString = truncateString(longString, 30);
console.log(truncatedString);

This snippet truncates a long string and appends an ellipsis if it exceeds a specified maximum length, enhancing text presentation.

10. Create a Countdown Timer

Example

function countdown(seconds)
{
  let timer = setInterval(() => { console.log(seconds);
  seconds--; if (seconds < 0) { clearInterval(timer);
  console.log("Countdown complete! check it in console"); } }, 1000);
} 
countdown(5);

Using setInterval, this snippet creates a countdown timer that fires a callback function every second until the countdown is complete.

11. Adding Event Listeners

The addEventListener method lets you attach event listeners to HTML elements, enhancing interactivity. The following example adds a click event to a button, which triggers a function when the button is clicked. One way to add event listeners in JavaScript is to use the addEventListener() method. This method attaches an event handler function to an element that is invoked when a specified event occurs.

Example

// Get the button element by its id
var button = document.getElementById("my-button");
// Define a function that alerts a message when the button is clicked
function handleClick() {
alert("You clicked the button!");
}
// Add a click event listener to the button element
button.addEventListener("click", handleClick);

This code will get the button element by its id and assign it to the button variable. Then, it will define a function that alerts a message when the button is clicked and assigns it to the handleClick variable. Finally, it will add a click event listener to the button element and pass the handleClick function as the second argument. The addEventListener() method can be used with different types of events, such as mouse events, keyboard events, or touch events.

12. Toggling Class Names

The classList.toggle method simplifies adding and removing classes from an element. This example toggles the 'active' class on a button when clicked. One way to toggle class names in JavaScript is to use the class list.toggle() method. This method adds a class name to an element if it does not have it or removes it if it does.

Example

// Get the div element by its id
var div = document.getElementById("my-div");
// Define a function that toggles the "red" class name on the div element
function toggleRed() {
div.classList.toggle("red");
}
// Add a click event listener to the div element that calls the toggleRed function
div.addEventListener("click", toggleRed);

This code will get the div element by its id and assign it to the div variable. Then, it will define a function that toggles the "red" class name on the div element and assign it to the toggled variable. Finally, it will add a click event listener to the div element that calls the toggled function when the div is clicked. The classList.toggle() method can be used with different types of elements, such as buttons, images, or links.

13. Arrow Functions

Arrow functions provide a concise syntax for writing functions. They are especially useful for short and one-line functions. One way to write arrow functions in JavaScript is to use the => operator. This operator creates a function expression that has a shorter syntax and does not bind its value.

Example

// Define a regular function that adds two numbers
function add(a, b) {
return a + b;
}
// Define an arrow function that does the same thing
var add = (a, b) => a + b;
// Call both functions and compare the results
console.log(add(2, 3)); // 5
console.log(add(2, 3)); // 5

This code will define two functions that add two numbers and assign them to the add variable. The first function is a regular function that uses the function keyword and has a return statement. The second function is an arrow function that uses the => operator and has an implicit return. Both functions will produce the same result when called with the same arguments. The arrow function has a shorter and simpler syntax than the regular function. However, it also has some differences in how it handles this value, the arguments object, and the prototype property.

14. Template Literals

Template literals offer an elegant way to concatenate strings and embed variables. One way to write template literals in JavaScript is to use the backtick (`) character. This character allows you to create strings that can include variables, expressions, or other features without using concatenation or escaping.

Example

var name = "Alice";
var age = 21;
var city = "Paris";
// Create a template literal using backticks
var message = `Hello, my name is ${name} and I am ${age} years old. I live in ${city}.`;
// Print the message to the console
console.log(message); // Hello, my name is Alice and I am 21 years old. I live in Paris.

This code will create a template literal using backticks and assign it to the message variable. The template literal can include variables, expressions, or other features inside curly braces and preceded by a dollar sign (${}). These are called template expressions, and they are evaluated and replaced by their values when the template literal is executed. The template literal can also include line breaks, whitespace, or other characters without using escape sequences. The console will print the message with the values of the variables and expressions inserted.

15. Destructuring Assignments

Destructuring assignments enable you to extract values from objects or arrays easily. One way to write destructuring assignments in JavaScript is to use the { } or [ ] syntax. This syntax allows you to unpack values from arrays or properties from objects and assign them to variables.

Example

var arr = [1, 2, 3, 4, 5];
// Destructure the array and assign the first and third elements to variables
var [a, , b] = arr;
// Print the values of the variables
console.log(a); // 1
console.log(b); // 3

This code will destructure the arr array and assign the first and third elements to the a and b variables. The [ ] syntax matches the elements of the array with the variables inside the brackets. The commas (,) are used to skip over the elements that are not needed. The console will print the values of the a and b variables.

16. Spread Operator

The spread operator unpacks elements from an array or properties from an object. One way to write a spread operator in JavaScript is to use the ... syntax. This syntax allows you to expand an iterable (such as an array, a string, or an object) into individual elements or properties.

Example

var arr = [1, 2, 3, 4, 5];
// Use the spread operator to copy the array into a new array
var copy = [...arr];
// Use the spread operator to insert the array elements into another array
var concat = [0, ...arr, 6];
// Print the values of the arrays
console.log(arr); // [1, 2, 3, 4, 5]
console.log(copy); // [1, 2, 3, 4, 5]
console.log(concat); // [0, 1, 2, 3, 4, 5, 6]

This code will use the spread operator to copy the arr array into a new array and assign it to the copy variable. The ... syntax will expand the arr array into its elements and pass them as arguments to the array literal. The code will also use the spread operator to insert the arr array elements into another array and assign it to the concat variable. The ... syntax will expand the arr array into its elements and place them between the other elements of the array literal. The console will print the values of the arr, copy, and concat arrays.

17. Rest Parameter

The rest parameter gathers the remaining arguments into an array. One way to write rest parameters in JavaScript is to use the ... syntax. This syntax allows you to represent an indefinite number of arguments as an array.

Example

function sum(...nums) {
var total = 0;
for (var num of nums) {
total += num;
}
return total;
}
// Call the function with different numbers of arguments
console.log(sum(1, 2, 3)); // 6
console.log(sum(4, 5)); // 9
console.log(sum(6)); // 6
console.log(sum()); // 0

This code will define a function that takes a rest parameter and returns the sum of its elements. The ... syntax will collect all the arguments passed to the function and store them in an array called nums. The function will then loop through the array and add each element to a variable called total. The function will return the value of the total. The console will print the result of calling the function with different numbers of arguments.

18. Default Parameters

Default parameters allow you to set default values for function arguments. One way to write default parameters in JavaScript is to use the = operator. This operator allows you to assign a default value to a parameter if it is not provided or undefined.

Example

function multiply(a, b = 1) {
return a * b;
}
// Call the function with different numbers of arguments
console.log(multiply(2, 3)); // 6
console.log(multiply(4)); // 4
console.log(multiply()); // NaN

This code will define a function that takes two parameters and returns their product. The second parameter has a default value of 1, which means that if it is not provided or undefined, it will be assigned to 1. The function will then return the product of the two parameters. The console will print the result of calling the function with different numbers of arguments.

19. Promises

Promises facilitate handling asynchronous operations in a more organized manner. One way to write promises in JavaScript is to use the new Promise() constructor. This constructor takes a function as an argument, which has two parameters: resolve and reject. These parameters are functions that can be called to fulfill or reject the promise.

Example

function getNumber() {
return new Promise(function(resolve, reject) {
var num = Math.floor(Math.random() * 10) + 1;
if (num % 2 == 0) {
resolve(num);
}
else {
reject("The number is odd");
}
});
}

getNumber()
.then(function(num) {
console.log("The number is " + num);
})
.catch(function(error) {
console.log(error);
});

This code will define a function that returns a promise and assigns it to the getNumber variable. The function will create a new promise using the new Promise() constructor and pass a function that generates a random number and resolves or rejects the promise based on its parity. The code will then call the function and handle the promise using the then() and catch() methods. The then() method takes a function that is executed when the promise is resolved and receives the resolved value as an argument. The catch() method takes a function that is executed when the promise is rejected and receives the rejected reason as an argument. The console will print either the number or the error message depending on the outcome of the promise.

20. Async/Await Async/await

simplifies working with promises, making asynchronous code look more synchronous. One way to write async/await in JavaScript is to use the async and await keywords. These keywords allow you to write asynchronous code that looks like synchronous code.

Example

async function getNumber() {
var num = Math.floor(Math.random() * 10) + 1;
return new Promise(function(resolve, reject) {
setTimeout(function() {
resolve(num);
}, 1000);
});
}

async function printNumber() {
var num = await getNumber();
console.log("The number is " + num);
}
printNumber();

21. Map

The map method applies a function to each element of an array and returns a new array with the results. One way to write a map in JavaScript is to use the map() method. This method creates a new array with the results of calling a function on every element in the original array.

Example

var arr = [1, 2, 3, 4, 5];
function double(num) {
return num * 2;
}
var newArr = arr.map(double);
console.log(arr); // [1, 2, 3, 4, 5]
console.log(newArr); // [2, 4, 6, 8, 10]

This code will define and assign an array of numbers to the arr variable. Then, it will define a function that doubles a number and assigns it to the double variable. Next, it will use the map() method to create a new array with the doubled numbers and assign it to the newArr variable. The map() method takes a function as an argument and calls it on every element of the original array. The function returns a new value for each element and the map() method collects these values into a new array.

22. Filter

The filter method creates a new array with elements that pass a given test function. One way to write a filter in JavaScript is to use the filter() method. This method creates a new array with the elements that pass a test implemented by a function.

Example

var arr = [1, 2, 3, 4, 5];
function isEven(num) {
return num % 2 == 0;
}
var newArr = arr.filter(isEven);
console.log(arr); // [1, 2, 3, 4, 5]
console.log(newArr); // [2, 4]

This code will define and assign an array of numbers to the arr variable. Then, it will define a function that checks if a number is even and assigns it to the isEven variable. Next, it will use the filter() method to create a new array with the even numbers and assign it to the newArr variable. The filter() method takes a function as an argument and calls it on every element of the original array. The function returns a boolean value that indicates whether the element should be included in the new array or not.

23. Object.entries()

Object.entries convert an object into an array of key-value pairs. One way to write Object.entries() in JavaScript is to use the Object.entries() method. This method returns an array of key-value pairs for an object.

Example

var obj = {
name: "Alice",
age: 21,
city: "Paris"
};
var arr = Object.entries(obj);
console.log(obj); // { name: 'Alice', age: 21, city: 'Paris' }
console.log(arr); // [ [ 'name', 'Alice' ], [ 'age', 21 ], [ 'city', 'Paris' ] ]

This code will define an object with some properties and assign it to the obj variable. Then, it will use the Object.entries() method to get an array of key-value pairs for the object and assign it to the arr variable. The Object.entries() method takes an object as an argument and returns an array of arrays, where each subarray contains the key and the value of a property. The console will print the values of the obj and arr variables.

24. Array Shuffling

One way to write array shuffling in JavaScript is to use the Fisher-Yates algorithm. This algorithm randomly swaps each element of the array with another element in the same or lower index.

Example

var arr = [1, 2, 3, 4, 5];
function shuffle(array) {
var len = array.length;
for (var i = len - 1; i > 0; i--) {
var j = Math.floor(Math.random() * (i + 1));
var temp = array[i];
array[i] = array[j];
array[j] = temp;
}
return array;
}
var newArr = shuffle(arr);
console.log(arr); // [5, 2, 4, 1, 3]
console.log(newArr); // [5, 2, 4, 1, 3]

This code will define and assign an array of numbers to the arr variable. Then, it will define a function that shuffles an array using the Fisher-Yates algorithm and assign it to the shuffle variable. Next, it will use the shuffle function to create a new shuffled array and assign it to the newArr variable. The shuffle function will loop through the array from the last element to the first and randomly swap each element with another element in the same or lower index. The console will print the values of the arr and newArr arrays.

25. Flatten an Array

Flattening an array means converting a nested array (an array containing sub-arrays) into a single-dimensional array, where all the elements are at the same level. This process involves recursively extracting elements from all levels of nesting and combining them into a new array. One way to flatten an array in JavaScript is to use the flat() method. This method creates a new array with all subarray elements concatenated into it recursively up to a specified depth.

Example

var arr = [[1, 2], [3, 4], [5, 6]];
var newArr = arr.flat();
console.log(arr); // [[1, 2], [3, 4], [5, 6]]
console.log(newArr); // [1, 2, 3, 4, 5, 6]

This code will define an array of arrays and assign it to the arr variable. Then, it will use the flat() method to create a new flattened array and assign it to the newArr variable. The flat() method takes an optional argument that specifies the depth of flattening. By default, it is 1, which means that only one level of nested arrays will be flattened. The console will print the values of the arr and newArr arrays.

Conclusion

JavaScript snippets are invaluable resources that empower developers to write efficient code and save time during development. In this article, we explored 25 of the best JavaScript snippets, along with practical examples to illustrate their application in real-world scenarios. By incorporating these snippets into your projects, you can streamline your development process and enhance your JavaScript coding skills.

FAQ's

Q1: What are JavaScript code snippets, and how do they work?

JavaScript code snippets are small, reusable pieces of code that perform specific tasks. They work by providing shortcuts for commonly used functionalities, allowing developers to insert pre-written code into their projects, saving time and effort.

Q2: How can JavaScript code snippets enhance my productivity?

Code snippets streamline the coding process, helping you write code more efficiently. By reusing code blocks, you can avoid repetitive tasks, focus on solving higher-level problems, and accelerate development timelines.

Q3: Are code snippets suitable for beginners in JavaScript?

Yes, code snippets are excellent learning tools for beginners. They offer well-crafted examples that demonstrate how specific functionalities are implemented. As beginners analyze and use snippets, they gain insights into JavaScript best practices.

Q4: Can I create my own JavaScript code snippets?

Absolutely! You can create personalized code snippets for your frequently used code patterns. Many modern IDEs and text editors allow users to define and use custom snippets, making it easier to tailor them to your coding style.

Q5: How do code snippets promote code consistency and standardization?

Code snippets enforce consistent coding patterns across projects. By using predefined snippets, developers adhere to standardized practices, ensuring code uniformity and making it easier for team members to collaborate effectively.

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