Use promises instead of async in font concatenation (remove async dependency)

package.json

@@ -22,7 +22,6 @@
     "@mapbox/mapbox-gl-native": "3.4.4",
     "@mapbox/sphericalmercator": "1.0.5",
     "advanced-pool": "0.3.2",
-    "async": "2.4.0",
     "base64url": "2.0.0",
     "canvas": "1.6.5",
     "clone": "2.1.1",

src/serve_font.js

@@ -36,19 +36,15 @@ module.exports = function(options, allowedFonts) {
     var fontstack = decodeURI(req.params.fontstack);
     var range = req.params.range;
 
-    return utils.getFontsPbf(options.serveAllFonts ? null : allowedFonts,
-      fontPath, fontstack, range, existingFonts,
-        function(err, concated) {
-      if (err || concated.length === 0) {
-        console.log(err);
-        console.log(concated.length);
-        return res.status(400).send('');
-      } else {
+    utils.getFontsPbf(options.serveAllFonts ? null : allowedFonts,
+      fontPath, fontstack, range, existingFonts).then(function(concated) {
         res.header('Content-type', 'application/x-protobuf');
         res.header('Last-Modified', lastModified);
         return res.send(concated);
+      }, function(err) {
+        return res.status(400).send(err);
       }
-    });
+    );
   });
 
   app.get('/fonts.json', function(req, res, next) {

src/serve_rendered.js

@@ -91,9 +91,12 @@ module.exports = function(options, repo, params, id, dataResolver) {
             var parts = req.url.split('/');
             var fontstack = unescape(parts[2]);
             var range = parts[3].split('.')[0];
-            utils.getFontsPbf(null, options.paths[protocol], fontstack, range, existingFonts,
-                function(err, concated) {
-              callback(err, {data: concated});
+            utils.getFontsPbf(
+              null, options.paths[protocol], fontstack, range, existingFonts
+            ).then(function(concated) {
+              callback(null, {data: concated});
+            }, function(err) {
+              callback(err, {data: null});
             });
           } else if (protocol == 'mbtiles') {
             var parts = req.url.split('/');

src/serve_style.js

@@ -117,7 +117,5 @@ module.exports = function(options, repo, params, id, reportTiles, reportFont) {
     });
   });
 
-  return new Promise(function(resolve, reject) {
-    resolve(app);
-  });
+  return Promise.resolve(app);
 };

src/utils.js

@@ -1,7 +1,6 @@
 'use strict';
 
-var async = require('async'),
-    path = require('path'),
+var path = require('path'),
     fs = require('fs');
 
 var clone = require('clone'),
@@ -73,47 +72,47 @@ module.exports.fixTileJSONCenter = function(tileJSON) {
   }
 };
 
-module.exports.getFontsPbf = function(allowedFonts, fontPath, names, range, fallbacks, callback) {
-  var getFontPbf = function(allowedFonts, name, range, callback, fallbacks) {
+var getFontPbf = function(allowedFonts, fontPath, name, range, fallbacks) {
+  return new Promise(function(resolve, reject) {
     if (!allowedFonts || (allowedFonts[name] && fallbacks)) {
       var filename = path.join(fontPath, name, range + '.pbf');
       if (!fallbacks) {
         fallbacks = clone(allowedFonts || {});
       }
       delete fallbacks[name];
-      return fs.readFile(filename, function(err, data) {
+      fs.readFile(filename, function(err, data) {
         if (err) {
           console.error('ERROR: Font not found:', name);
           if (fallbacks && Object.keys(fallbacks).length) {
             var fallbackName = Object.keys(fallbacks)[0];
             console.error('ERROR: Trying to use', fallbackName, 'as a fallback');
             delete fallbacks[fallbackName];
-            return getFontPbf(null, fallbackName, range, callback, fallbacks);
+            getFontPbf(null, fontPath, fallbackName, range, fallbacks).then(resolve, reject);
           } else {
-            return callback(new Error('Font load error: ' + name));
+            reject('Font load error: ' + name);
           }
         } else {
-          return callback(null, data);
+          resolve(data);
         }
       });
     } else {
-      return callback(new Error('Font not allowed: ' + name));
+      reject('Font not allowed: ' + name);
     }
+  });
 };
 
+module.exports.getFontsPbf = function(allowedFonts, fontPath, names, range, fallbacks) {
   var fonts = names.split(',');
   var queue = [];
   fonts.forEach(function(font) {
-    queue.push(function(callback) {
-      getFontPbf(allowedFonts, font, range, callback, clone(allowedFonts || fallbacks));
-    });
+    queue.push(
+      getFontPbf(allowedFonts, fontPath, font, range, clone(allowedFonts || fallbacks))
+    );
   });
 
-  return async.parallel(queue, function(err, results) {
-    if (err) {
-      callback(err, new Buffer([]));
-    } else {
-      callback(err, glyphCompose.combine(results));
-    }
+  return new Promise(function(resolve, reject) {
+    Promise.all(queue).then(function(values) {
+      return resolve(glyphCompose.combine(values));
+    }, reject);
   });
 };