javascript slider weighted values?

Question

I have a JavaScript slider that outputs a value between 0 and 1 depending on its position. I want to convert that value to a value on another scale between say 100 and 1000, but based on the distribution of a set of data points between 100 and 1000. The use case here is that I want the slider to be less sensitive to changes when there is a very close set of numbers. Eg... let's say the values in the scale are: 100, 200, 300, 500, 1000 The values 100-500 might take up, say, the first 80% of the slider due to their closer distribution, therefore making it easier to select between them. There's clearly a mathematical function for calculating this, perhaps involving standard deviation and coefficients. Anyone know what it is?

Answer 1

This is called Interpolation. In order to interpolate values from on scale to another, use the function below:

function lerp (inputValue, startRange, endRange){

return (1-inputValue)*startRange+inputValue*endRange;

}

You can then use for a range 100 - 500 as:

const output = lerg(0.1, 100, 500); // returns 140

output = lerg(0.3, 100, 500); // returns 220

output = lerg(0.6, 100, 500); // returns 340

output = lerg(0.9, 100, 500); // returns 460

output = lerg(1, 100, 500); // returns 500

Please let me know if you have any issue using it.