@material-ui/core/esm/styles/responsiveFontSizes.js

React components that implement Google's Material Design.

import _extends from "@babel/runtime/helpers/esm/extends";
import convertLength from 'convert-css-length';
import { responsiveProperty, alignProperty, fontGrid } from './cssUtils';

function isUnitless(value) {
  return String(parseFloat(value)).length === String(value).length;
}

export default function responsiveFontSizes(themeInput) {
  var options = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : {};
  var _options$breakpoints = options.breakpoints,
      breakpoints = _options$breakpoints === void 0 ? ['sm', 'md', 'lg'] : _options$breakpoints,
      _options$disableAlign = options.disableAlign,
      disableAlign = _options$disableAlign === void 0 ? false : _options$disableAlign,
      _options$factor = options.factor,
      factor = _options$factor === void 0 ? 2 : _options$factor,
      _options$variants = options.variants,
      variants = _options$variants === void 0 ? ['h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'subtitle1', 'subtitle2', 'body1', 'body2', 'caption', 'button', 'overline'] : _options$variants;

  var theme = _extends({}, themeInput);

  theme.typography = _extends({}, theme.typography);
  var typography = theme.typography; // Convert between css lengths e.g. em->px or px->rem
  // Set the baseFontSize for your project. Defaults to 16px (also the browser default).

  var convert = convertLength(typography.htmlFontSize);
  var breakpointValues = breakpoints.map(function (x) {
    return theme.breakpoints.values[x];
  });
  variants.forEach(function (variant) {
    var style = typography[variant];
    var remFontSize = parseFloat(convert(style.fontSize, 'rem'));

    if (remFontSize <= 1) {
      return;
    }

    var maxFontSize = remFontSize;
    var minFontSize = 1 + (maxFontSize - 1) / factor;
    var lineHeight = style.lineHeight;

    if (!isUnitless(lineHeight) && !disableAlign) {
      throw new Error(["Material-UI: unsupported non-unitless line height with grid alignment.", 'Use unitless line heights instead.'].join('\n'));
    }

    if (!isUnitless(lineHeight)) {
      // make it unitless
      lineHeight = parseFloat(convert(lineHeight, 'rem')) / parseFloat(remFontSize);
    }

    var transform = null;

    if (!disableAlign) {
      transform = function transform(value) {
        return alignProperty({
          size: value,
          grid: fontGrid({
            pixels: 4,
            lineHeight: lineHeight,
            htmlFontSize: typography.htmlFontSize
          })
        });
      };
    }

    typography[variant] = _extends({}, style, {}, responsiveProperty({
      cssProperty: 'fontSize',
      min: minFontSize,
      max: maxFontSize,
      unit: 'rem',
      breakpoints: breakpointValues,
      transform: transform
    }));
  });
  return theme;
}