I am needing to apply a kind of “validations” in the request script, I didn’t get anywhere though.
e.g: I need to get the standard deviation of a band using a function and its return should be less than 130, if it’s true, another comparison get done.
The problem is: I couldn’t find any way to access the pixels of the band to calculate the standard deviation, the pixels should be an array.
Someone have any idea how can I get the all pixels to apply my function?
Thank you in advance! 
The main idea of the script:
const standard_deviation = (band) => // here goes the formula using band pixels
if (standard_deviation(B02) < 200) {
if (standard_deviation(B08) < 100) {
// ... more validations
}
}