10 Different Ways To Loop Through Arrays of Objects in JavaScript

Looping through arrays of objects is a common task in JavaScript programming. Whether you’re working on a web app or a data analysis tool, being able to efficiently iterate through arrays can save you time and help you write more elegant code. In this post, we’ll explore ten different ways to loop through an array of objects in JavaScript, along with coding examples and explanations for each approach. From classic for loops to modern functional programming methods, you’re sure to find a looping strategy that fits your coding style and project requirements.

1. for loop

The for loop is a common way to loop through an array. It initializes a counter variable i to 0, and then continues looping as long as i is less than the length of the array. It increments i by 1 with each iteration.

const arr = [{name: 'John', age: 25}, {name: 'Jane', age: 30}, {name: 'Bob', age: 20}];

for(let i = 0; i < arr.length; i++) {
    console.log(arr[i]);
}

2. while loop

The while loop is another classic loop that can be used to iterate over an array. It continues looping as long as the condition in the parentheses is true.

const arr = [{name: 'John', age: 25}, {name: 'Jane', age: 30}, {name: 'Bob', age: 20}];

let i = 0;
while(i < arr.length) {
    console.log(arr[i]);
    i++;
}

3. do…while loop

The do…while loop is similar to the while loop, but it always executes the code block at least once, even if the condition in the parentheses is false.

const arr = [{name: 'John', age: 25}, {name: 'Jane', age: 30}, {name: 'Bob', age: 20}];

let i = 0;
do {
    console.log(arr[i]);
    i++;
} while(i < arr.length);

4. forEach() Method

The forEach() method is another way to loop through an array. It takes a function as an argument, which is called once for each item in the array.

const arr = [{name: 'John', age: 25}, {name: 'Jane', age: 30}, {name: 'Bob', age: 20}];

arr.forEach(item => {
    console.log(item);
});

5. for…of loop

The for…of loop is similar to the for loop, but it iterates over the values in the array instead of the indices.

const arr = [{name: 'John', age: 25}, {name: 'Jane', age: 30}, {name: 'Bob', age: 20}];

for(let item of arr) {
    console.log(item);
}

6. map() method

The map() method is similar to forEach(), but it returns a new array based on the function that is called for each item in the array.

const arr = [{name: 'John', age: 25}, {name: 'Jane', age: 30}, {name: 'Bob', age: 20}];

arr.map(item => {
    console.log(item);
});

7. reduce() method

The reduce() method can also be used to loop through an array. It takes a function as an argument that takes an accumulator and the current item in the array. The function returns the accumulator, which can be used to accumulate values as the array is looped through.

const arr = [{name: 'John', age: 25}, {name: 'Jane', age: 30}, {name: 'Bob', age: 20}];

arr.reduce((acc, item) => {
    console.log(item);
    return acc;
}, {});

8. filter() method

The filter() method can be used to loop through an array and filter out items based on a condition. It takes a function as an argument that returns true or false, depending on whether the item should be included in the filtered array.

const arr = [{name: 'John', age: 25}, {name: 'Jane', age: 30}, {name: 'Bob', age: 20}];

arr.filter(item => {
    console.log(item);
    return true;
});

9. some() method

The some() method can be used to loop through an array and check if at least one item meets a condition. It takes a function as an argument that returns true or false.

const arr = [{name: 'John', age: 25}, {name: 'Jane', age: 30}, {name: 'Bob', age: 20}];

arr.some(item => {
    console.log(item);
    return false;
});

10. every() method

The every() method is similar to some(), but it checks if every item in the array meets a condition.

const arr = [{name: 'John', age: 25}, {name: 'Jane', age: 30}, {name: 'Bob', age: 20}];

arr.every(item => {
    console.log(item);
    return true;
});

Conclusion

With these ten different ways to loop through an array of objects, you have a variety of tools to choose from depending on your coding preferences and project requirements. Whether you need to filter out specific items, accumulate values, or simply log each object in the array, there’s a looping strategy that can get the job done.