const calcHeading = (
  heading: number,
  fontSize: string,
  lineHeight: number,
  breakpoints: {},
  mediaQuery: MediaQueryOptionsProps,
): FlattenSimpleInterpolation => {
  if (Object.entries(breakpoints).length === 0) {
    throw new Error('Cant be empty @todo error message');
  }

  const size = stripUnit(em(fontSize));
  const lineHeightSpacing = (factor = 1): number => {
    return size * lineHeight * factor;
  };
  const spacingValue = lineHeightSpacing();
  const mediaqueries: string[] = [];

  for (const key in breakpoints) {
    if (Array.isArray(breakpoints[key])) {
      const calcSize = size * breakpoints[key][heading];
      let calcLineHeight = 0;
      let multiplier = 1;

      if (calcSize <= spacingValue) {
        calcLineHeight = spacingValue / calcSize;
      } else {
        while (lineHeightSpacing(multiplier) < calcSize) {
          multiplier += 0.5;
        }

        calcLineHeight = lineHeightSpacing(multiplier) / calcSize;
      }

      mediaqueries.push(mediaquery(key, mediaQuery)`
        font-size: ${em(calcSize, size)};
        line-height: ${calcLineHeight};
        font-weight: 700;
      `);
    }
  }

  return css`
    ${mediaqueries}
  `;
};

 font-size: ${props => em(props.theme.fontSize)};

 font-size: ${props => em(props.theme.typography.fontSize)};