fix: Use buffer for memory-fs readFile signature

Author: jantimon

lib/icons-to-woff.js

@@ -46,17 +46,17 @@ module.exports = function createIconFont (fs, icons, options) {
         }
       });
       fontStream.write(glyph);
-      fs.readFile(filename, 'utf-8', function (err, result) {
+      fs.readFile(filename, function (err, svgBuffer) {
         if (err) {
           return reject(err);
         }
-        const iconHeight = getSvgHeight(result, filename);
+        // prevent svgs with fill="none" from beeing translated into an empty symbol
+        const svgCode = svgBuffer.toString().replace(/\sfill\s*=\s*["']?none['"]?/ig, '')
+        const iconHeight = getSvgHeight(svgCode, filename);
         if (!iconHeight) {
           return reject(new Error(`SVG font generation failed as icon "${filename}" does not have a height.`));
         }
-        // prevent svgs with fill="none" from beeing translated into an empty symbol
-        result = result.replace(/\sfill\s*=\s*["']?none['"]?/ig, '');
-        glyph.push(result);
+        glyph.push(svgCode);
         glyph.push(null);
       });
     });