1-off error in MobileStepper

[ScottieR]

• This is a v1.x issue.
• I have searched the issues of this repository and believe that this is not a duplicate.

Expected Behavior

Mobile stepper should show correct percentage of steps in progress bar

Current Behavior

Right now it's calculating the percentage complete based on (active step)/(total steps - 1) * 100. This gives weird results where the progress is 0 on first step, 33% on second, 66% on third and 100% on fourth. It should either show 0 on step 1 and 75% on last step, or (and probably preferred) 25% on first step and 100% on last step. So: (active step + 1) / (total steps) * 100

Steps to Reproduce

Look at the existing demo on the demos page, which has 6 steps. Actually count and at step 3 of 6 the stepper is not 50%.

Link: https://material-ui.com/demos/steppers/

Context

We show "Step [x]/[total]" on our mobile stepper and it looks very weird when it's step 2/4 and not 50%

Your Environment

Tech	Version
Material-UI	v1.4.2

[oliviertassinari]

@ScottieR The MobileStepper accounts for the number of steps completed. It's opinionated. The specification seems to encourage (I have done the math with the number of pixels) the number of steps in progress: https://material.io/archive/guidelines/components/steppers.html#steppers-types-of-steps like you are suggesting. I fear changing the logic is a breaking change.

Maybe adding a LinearProgressProps property to change override the value would do it? Do you want to work on it?