# Flags in JavaScript functions

You can implicitly use flags in functions using the `return` statement. Let's see how it's done. Suppose we have the following function that checks that all array elements are positive numbers:

`function isPositive(arr) { let flag = true; for (let elem of arr) { if (elem < 0) { flag = false; } } return flag; }`

Let's rewrite the function code with implicit flags:

`function isPositive(arr) { for (let elem of arr) { if (elem < 0) { return false; } } return true; }`

How it works: if there is a required element in the array, we exit the function (and the loop too) with `return`. But if the required element is not found in the array, the function will not exit and execution will reach the command `return true`. And it turns out that the function will return `true` as a sign that all elements in the array are positive.

Make a function that takes an array of numbers as a parameter, and check that all elements in this array are even numbers.

Make a function that will take a number as a parameter and check that all digits of this number are odd.

Make a function that takes an array as a parameter and checks if there are two identical elements in a row in this array.

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