D3.js Interpolate

d3-interpolate provides methods for interpreting between values (numbers, colors, dates, and strings), arrays of values, objects, css transforms, svg transforms, and zoom values.

The number linear interpolator is just linear interpolation.

The string interpolator just linear interpolates between the numbers in each of the input strings.

The color interpolator allows you to interpolate between rgb, hsl, lab, hcl, and cubehelix colors.