Linear scale a number between ranges

Map a value from one range onto another.

JavaScript Version 1.0.0 · MIT · .md

function linearScale({ value, inMin, inMax, outMin, outMax }) { return ((value - inMin) * (outMax - outMin)) / (inMax - inMin) + outMin; }

Input & expected output

{
  "value": 5,
  "inMin": 0,
  "inMax": 10,
  "outMin": 0,
  "outMax": 100
}

50

The edge case

{
  "value": 0,
  "inMin": -1,
  "inMax": 1,
  "outMin": 100,
  "outMax": 0
}

50

Know the limits

• Output ranges may be reversed, as the edge case shows. The lab requires inMin ≠ inMax.

The function above is the implementation used by the lab. The lab validates JSON types and caps size before execution; include equivalent validation when accepting untrusted input in your application.

Keep exploring

• Convert degrees to radians — Multiply by π and divide by 180.
• Check if a rectangle contains another one — Compare corners: a contains b when b’s corners sit inside or on a’s edges.
• Check if a rectangle overlaps another one — Two rectangles overlap when they overlap on both axes.