5 Essential JavaScript Between Methods to Master in 2024

JavaScript is a versatile programming language used for web development. One common task developers face is checking if a value lies between two numbers or extracting specific substrings. This tutorial covers five essential methods related to the concept of "between" in JavaScript. By mastering these techniques, you can enhance your coding skills and streamline your projects.

Quick Code Example

Here's a simple example that shows how to check if a number is between two values:

1function isBetween(num, min, max) {
2    return num >= min && num <= max;
3}
4
5console.log(isBetween(5, 1, 10)); // true

This function checks if num is between min and max.

Understanding the Syntax

In JavaScript, there isn't a built-in "between" function. However, we can create our own using comparison operators. The basic syntax for our custom function looks like this:

1function isBetween(value, lowerBound, upperBound) {
2    // Logic here
3}

Parameters:

• value: The number to check.
• lowerBound: The minimum value.
• upperBound: The maximum value.

Return Value:

• Returns true if value is between lowerBound and upperBound; otherwise, returns false.

Example 1: Checking Number Range

Title: Check if a Number Falls Within a Range

Let's look at a practical example where we check if a score falls within a passing range:

1function isPassing(score) {
2    return isBetween(score, 60, 100);
3}
4
5console.log(isPassing(75)); // true
6console.log(isPassing(55)); // false

In this case, we determine if a score is passing by checking if it's between 60 and 100.

Example 2: Extracting Substrings

Title: Get String Between Parentheses

You might need to extract text between parentheses in a string. Here's how you can do that:

1function getStringBetween(str) {
2    const start = str.indexOf('(') + 1;
3    const end = str.indexOf(')');
4    return str.substring(start, end);
5}
6
7console.log(getStringBetween("Hello (world)")); // world

This function finds the text between the first pair of parentheses.

Example 3: Using Array Filter

Title: Filter Array Values

You can also use a custom "between" function with arrays. For example, filtering numbers within a specific range:

1const numbers = [1, 5, 8, 12, 15, 20];
2
3const filteredNumbers = numbers.filter(num => isBetween(num, 5, 15));
4console.log(filteredNumbers); // [5, 8, 12, 15]

This code filters the array to include only values between 5 and 15.

Example 4: Date Comparison

Title: Check If a Date is Within a Range

Another application is checking if a date falls within a specific range. Here’s how to do it:

1function isDateInRange(date, startDate, endDate) {
2    return date >= startDate && date <= endDate;
3}
4
5const today = new Date();
6const start = new Date('2024-01-01');
7const end = new Date('2024-12-31');
8
9console.log(isDateInRange(today, start, end)); // true or false

This function checks if today's date is within the year 2024.

Example 5: Working with Objects

Title: Filter Objects Based on Property Value

You can also filter objects based on a property value using our "between" logic:

1const people = [
2    { name: 'Alice', age: 25 },
3    { name: 'Bob', age: 30 },
4    { name: 'Charlie', age: 35 },
5];
6
7const filteredPeople = people.filter(person => isBetween(person.age, 28, 34));
8console.log(filteredPeople); // [{ name: 'Bob', age: 30 }]

This example filters an array of objects to find people within a certain age range.

Browser Compatibility

Most modern web browsers support these JavaScript features. You can expect consistent behavior across Chrome, Firefox, Safari, and Edge. However, always test your code in different environments to ensure compatibility.

Summary

In this tutorial, we explored essential concepts related to the idea of "between" in JavaScript. We learned how to create custom functions to check if numbers fall within a range and how to extract substrings. We provided examples that demonstrated various applications, from filtering arrays to working with dates and objects. Mastering these techniques will help you write cleaner and more efficient code. For further learning, consider checking out our JavaScript course or our HTML fundamentals course.

By understanding how to use these methods, you'll be better equipped to handle a variety of programming challenges. Happy coding!