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Asked: 2024-09-27T04:50:43+05:30 In:

How to Create a Custom Comparator Function for Sorting Objects in JavaScript?

I recently stumbled upon a really interesting challenge involving comparator functions in JavaScript, and I thought it would be fun to share and see how different folks approach it. So, here’s the deal: the goal is to create a custom comparator function that can sort an array based on various criteria. Sounds simple enough, right? But here’s where things get more intriguing.

Imagine you have an array of objects, where each object represents a person. Each person has a name and an age, like this:

“`javascript
const people = [
{ name: “Alice”, age: 25 },
{ name: “Bob”, age: 22 },
{ name: “Charlie”, age: 30 },
{ name: “Diana”, age: 25 }
];
“`

Now, you want to sort this array based on two criteria. First, you want to sort by age in ascending order. But here’s where it gets fun: if two people are the same age, you want to sort them by their names in alphabetical order.

So, the output should look like this:

“`javascript
[
{ name: “Bob”, age: 22 },
{ name: “Alice”, age: 25 },
{ name: “Diana”, age: 25 },
{ name: “Charlie”, age: 30 }
]
“`

What’s tricky is writing a comparator function that handles both criteria efficiently. If you’ve done some sorting in JavaScript before, you probably used the `.sort()` method. But how would you craft a comparator function that gets this double sort to work seamlessly?

I’m really curious to see your solutions! What are your thoughts? Would you use a separate function to define the logic, or would you inline everything? Also, how do you plan to handle cases where ages are the same—will you take care of case sensitivity in names?

I’d love to see some creative approaches, too! Whether you’re a seasoned pro or just diving into JavaScript, I think it’ll be fun to compare our techniques. So, what do you say? How would you write this comparator function? Let’s get those coding juices flowing!

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    2 Answers

    1. Sorting an Array of People

      So, I really wanted to sort this array of people by their age and name, and here’s what I came up with!

              
const people = [
    { name: "Alice", age: 25 },
    { name: "Bob", age: 22 },
    { name: "Charlie", age: 30 },
    { name: "Diana", age: 25 }
];

const customSort = (a, b) => {
    // First, compare ages
    if (a.age < b.age) {
        return -1; // a comes first
    }
    if (a.age > b.age) {
        return 1; // b comes first
    }
  
    // If ages are the same, compare names
    // Using localeCompare for case insensitive sort
    return a.name.localeCompare(b.name);
};

// Now we just sort the array using our custom comparator
people.sort(customSort);

console.log(people);

      So this should give us the array sorted by age, and if ages are the same, it sorts by name! I used `localeCompare` because it takes care of case sensitivity, which is pretty neat. How does this approach look? I’m curious to hear what others think, or if there’s an even better way to do it!

    2. To tackle the sorting challenge using a custom comparator function in JavaScript, we can utilize the built-in `.sort()` method effectively. The comparator function will first compare the ages of the individuals. If the ages are the same, we then proceed to compare their names in alphabetical order. Below is a concise implementation of the comparator function: 

      
const people = [
    { name: "Alice", age: 25 },
    { name: "Bob", age: 22 },
    { name: "Charlie", age: 30 },
    { name: "Diana", age: 25 }
];

people.sort((a, b) => {
    // Compare ages first
    if (a.age !== b.age) {
        return a.age - b.age; // Ascending order for age
    }
    // If ages are the same, compare names alphabetically
    return a.name.localeCompare(b.name);
});

console.log(people);

      In this implementation, we are using the expression `a.age – b.age` to achieve ascending order by age. The `localeCompare` method is used to handle the alphabetical sorting of names, which naturally manages case sensitivity, making it suitable for our needs. This approach keeps the code clean and easy to read, while allowing for efficient handling of the sorting logic within a single inline function in the `.sort()` method. The output will match the expected result you provided, ensuring our custom comparator function is effectively addressing the requirements.

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