ee.Image.unitScale

Scales the input so that the range of input values [low, high] becomes [0, 1]. Values outside the range are NOT clamped. This algorithm always produces floating point pixels.
UsageReturns
Image.unitScale(low, high)Image
ArgumentTypeDetails
this: inputImageThe image to scale.
lowFloatThe value mapped to 0.
highFloatThe value mapped to 1.