[SASS/SCSS] `image-width` and `image-height` asset functions (mixins)

sass-asset-functions.js

const path = require('path');
const sass = require('node-sass');
const imageSizeOf = require('image-size');

module.exports = {
  'image-width($imageUrl)': function (imageUrl) {
    const absoluteImagePath = this.options.includePaths.split(':').pop();
    const absoluteImageUrl = path.resolve(absoluteImagePath, imageUrl.getValue());
    const dimensions = imageSizeOf(absoluteImageUrl);

    return sass.types.Number(dimensions.width, 'px');
  },
  'image-height($imageUrl)': function (imageUrl) {
    const absoluteImagePath = this.options.includePaths.split(':').pop();
    const absoluteImageUrl = path.resolve(absoluteImagePath, imageUrl.getValue());
    const dimensions = imageSizeOf(absoluteImageUrl);

    return sass.types.Number(dimensions.height, 'px');
  }
};