# How to Create an Array from a Range of Numbers in JavaScript?

To create an array from a range of numbers in JavaScript, you can use the same approach as creating an array from a range of two numbers, but you can make the function more flexible by allowing for a step or increment value. This means you can specify the amount by which to increase or decrease the number in each iteration of the loop.

Here’s an example code snippet that demonstrates how to create an array from a range of numbers in JavaScript with an optional step parameter:

``````function createRangeArray(start, end, step = 1) {
const rangeArray = [];

if (step > 0) {
for (let i = start; i <= end; i += step) {
rangeArray.push(i);
}
} else {
for (let i = start; i >= end; i += step) {
rangeArray.push(i);
}
}

return rangeArray;
}

const newArray = createRangeArray(1, 10, 2);
console.log(newArray); // [1, 3, 5, 7, 9]

const newArray2 = createRangeArray(10, 1, -2);
console.log(newArray2); // [10, 8, 6, 4, 2]``````

In this code, the `createRangeArray()` function takes three arguments: `start`, `end`, and an optional `step` value which defaults to `1`.

Inside the function, an empty array called `rangeArray` is declared. Then, an `if-else` statement is used to check if the `step` value is positive or negative. If it’s positive, a `for` loop is used to iterate from the `start` number to the `end` number with the specified `step`. In each iteration, the loop pushes the current number into the `rangeArray`. If `step` is negative, the loop decrements `i` by `step` until it reaches `end`.

Finally, the `rangeArray` is returned from the function, and its value is assigned to a new variable called `newArray` and `newArray2`. We have passed the arguments `1`, `10`, and `2` to the `createRangeArray()` function to create an array from the range of numbers between 1 and 10 with an increment of 2, and then we log the resulting array to the console. We have also passed the arguments `10`, `1`, and `-2` to create an array from the range of numbers between 10 and 1 with a decrement of 2, and then we log the resulting array to the console.