# Every element in array should match condition

## Every element in array should match condition

As a programmer, we often come across a situation where we need to check whether all the elements in an array fulfill a certain condition or not. There are several ways to achieve this and let's discuss them one by one:

### Using Array.every() method

The Array.every() method tests whether all elements in the array pass the test implemented by the provided function. It returns a Boolean value indicating whether all elements pass the test or not.

const arr = [1, 2, 3, 4, 5];

const isGreaterThanZero = (element) => element > 0;

console.log(arr.every(isGreaterThanZero)); // Output: true

In the above example, we have an array of numbers and we want to check whether all the elements are greater than zero or not. We define a function isGreaterThanZero which checks whether an element is greater than zero or not. Then we use the Array.every() method to check whether all elements pass this condition or not. Since all elements are greater than zero, the output will be true.

### Using for loop

We can also use a for loop to iterate over the array and check whether all elements fulfill the condition or not.

const arr = [1, 2, 3, 4, 5];
let allGreaterThanZero = true;

for (let i = 0; i < arr.length; i++) {
if (arr[i] <= 0) {
allGreaterThanZero = false;
break;
}
}

console.log(allGreaterThanZero); // Output: true

In the above example, we initialize a boolean variable allGreaterThanZero to true. Then we loop through the array and check whether each element is greater than zero or not. If we find an element that is not greater than zero, we set allGreaterThanZero to false and break out of the loop. Finally, we check whether allGreaterThanZero is still true or not. If it is true, then all elements fulfill the condition.

### Using Array.filter() method

We can also use the Array.filter() method to filter out the elements that do not fulfill the condition and then check whether the length of the resulting array is equal to the length of the original array.

const arr = [1, 2, 3, 4, 5];

const isGreaterThanZero = (element) => element > 0;

const filteredArr = arr.filter(isGreaterThanZero);

console.log(filteredArr.length === arr.length); // Output: true

In the above example, we define a function isGreaterThanZero which checks whether an element is greater than zero or not. Then we use the Array.filter() method to filter out the elements that do not fulfill this condition. The resulting array will only contain elements that are greater than zero. Finally, we check whether the length of the resulting array is equal to the length of the original array or not. If they are equal, then all elements fulfill the condition.

### Conclusion

In this post, we discussed three different ways to check whether all elements in an array fulfill a certain condition or not. It is important to choose the right method based on the situation and the specific requirements of the task at hand.

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