index.js

'use strict';

const fs = require('fs');
const path = require('path');
const postcss = require('postcss');
const url = require('url');

const DEFAULT_OPTS = {
  checkFiles: false,
  ie8Fix: false,
  formats: [
    { type: 'embedded-opentype', ext: 'eot' },
    { type: 'woff2', ext: 'woff2' },
    { type: 'woff', ext: 'woff' },
    { type: 'truetype', ext: 'ttf' },
    { type: 'opentype', ext: 'otf' },
    { type: 'svg', ext: 'svg'}
  ]
};

module.exports = postcss.plugin('postcss-fontpath', opts => {

  const config = Object.assign({}, DEFAULT_OPTS, opts || {});

  return function(css) {
    // Loop through each @rule
    css.walkAtRules('font-face', rule => {

      // Loop through each decleration in the rule
      rule.walkDecls('font-path', decl => {

        // Replace single and double quotes with nothing
        let fontPath = decl.value.replace(/"/g, '').replace(/'/g, ''),
            fonts = [],
            ieHack = false,
            ext = '';

        config.formats.forEach(format => {

          if (config.checkFiles) {
            // Best guess at where our fonts might be relative to
            let basePath = css.source.input.file || process.cwd(),
                absoluteFontPath = url.parse(path.resolve(path.dirname(basePath), fontPath) + '.' + format.ext).pathname;

            try {
              // Try to see if the font exists
              fs.accessSync(absoluteFontPath, fs.F_OK);
            } catch (err) {
              return;
            }
          }

          // Set the ext var
          ext = format.ext;

          if (ext === 'eot' && config.ie8Fix) {
            ieHack = true;
            ext = 'eot?#iefix';
          }

          // Add the font to the font-face decl
          fonts.push('url("' + fontPath + '.' + ext + '") format(\'' + format.type + '\')');
        });

        if (fonts.length > 0) {

          // If the EOT exists, add the fallback
          if (ieHack && config.ie8Fix) {
            decl.cloneBefore({
              prop: 'src',
              value: 'url("' + fontPath + '.eot")'
            });
          }

          // Implode the rest of the fonts
          decl.cloneBefore({
            prop: 'src',
            value: fonts.join(',\n       ')
          });
        }

        // Remove our custom decleration
        decl.remove();
      });
    });
  };
});