@mui/material/modern/Link/getTextDecoration.js

import { alpha, getPath } from '@mui/system';
export const colorTransformations = {
  primary: 'primary.main',
  textPrimary: 'text.primary',
  secondary: 'secondary.main',
  textSecondary: 'text.secondary',
  error: 'error.main'
};

const transformDeprecatedColors = color => {
  return colorTransformations[color] || color;
};

const getTextDecoration = ({
  theme,
  ownerState
}) => {
  const transformedColor = transformDeprecatedColors(ownerState.color);
  const color = getPath(theme, `palette.${transformedColor}`, false) || ownerState.color;
  const channelColor = getPath(theme, `palette.${transformedColor}Channel`);

  if ('vars' in theme && channelColor) {
    return `rgba(${channelColor} / 0.4)`;
  }

  return alpha(color, 0.4);
};

export default getTextDecoration;