**`every()`** is a built-in method we can use with the `Array` type in JavaScript.

The following is the method prototype:

```javascript
Array.every(function(currentValue, index, arr), thisValue)
```

# Parameters and return value

The method takes the following input parameters:

- `function`: This is the callback function that implements a specific condition.

- `currentValue`: The value of the current element being processed in the array.

- `index`: The index of the current element. This parameter is optional.

- `arr`: The array for which the `every()` function is called. This parameter is optional.

- `thisValue`: A value to be passed to the method as the `this` value of the callback function. This parameter is optional.

The `every()` method executes the callback function for each element of the array. If the callback function returns `false`, the `every()` method also returns `false` and does not evaluate any remaining elements.

If the callback function returns `true` for all elements of the array, the `every()` method also returns `true`, meaning that every element within the array meets the specified condition.


# Functionality

Suppose you have an array of *n* elements and you want to check if all of the elements are greater than 10. Such tasks can typically be completed using `for` loops.

The `every()` method offers the same functionality but without the use of cumbersome loops.

The `every()` method is used to check if all of the elements within an array meet a specified condition.

The *condition* is implemented in the form of a callback function. This makes the code concise and easier to read.

// define an array
var arr = [5, 3, 1, 9, 7];

// define callback function
function isPositive(currentValue)
{
    return currentValue > 0;
}

// printing the result
console.log("Array contains all positive numbers: " + arr.every(isPositive));

// define callback function
function isEven(currentValue)
{
    return (currentValue % 2 === 0);
}

// printing the result
console.log("Array contains all even numbers: " + arr.every(isEven));

// define embedded callback function
var result = arr.every(function(currentValue){
    return (currentValue % 2 !== 0);
})

// printing the result
console.log("Array contains all odd numbers: " + result);

In the above example, we begin by declaring an array of 5 random numbers.

Then we define our first callback function (`isPositive`) that only takes the *currentValue* as input. The function checks whether the array contains all positive numbers. As our array does contain only positive numbers, the `every()` method returns `true`.

Moving on, we define a second callback function (`isEven`). The function checks whether the *currentValue* is even. As our array contains no even numbers, the `every()` method returns `false`.

Finally, we define a third callback function. This time, we have embedded the callback function within the `every()` method call. This means that we can skip out on giving our callback function a name. The function checks whether the array contains all odd numbers. As our array does contain only odd numbers, the `every()` method returns `true`.

What is the every method in JavaScript Arrays?

every() checks if all array elements satisfy a specific condition using a callback function, returning true or false accordingly.

What is the every method in JavaScript Arrays?

Parameters and return value

Functionality

Code