PostCSS plugin that generates REM based font-size and line-height for every fontsize declaration. The line-height will be 1.5 times the fontsize value. A fallback option using pixel based font-size and line-height can also be generated.

h1 {
    fontsize: 16
}

Output:

h1 {
  font-size: 1rem;
  line-height: 1.5rem;
}

Usage

npm install postcss-fontsize --save-dev

Gulp

var postcss = require('gulp-postcss');
var fontsize = require('postcss-fontsize');
gulp.task('css', function () {
    var processors = [
        fontsize
    ];
    return gulp.src('./src/*.css')
        .pipe(postcss(processors))
        .pipe(gulp.dest('./dest'));
});

Options

The plugin does not generate fallback px sizes by default. In order generate the px fallbacks include the following option in the gulp task:

var processors = [
	fontsize({
		fallback: true
	})
];

Including fallback option:

h1 {
    fontsize: 16
}

Output:

h1 {
  font-size: 16px;
  line-height: 24px;
  font-size: 1rem;
  line-height: 1.5rem;
}

See PostCSS docs for examples for your environment.