allow asyncronous compileFile and renderFile operations. Fixes gh-283

lib/swig.js

@@ -473,25 +473,23 @@ exports.Swig = function (opts) {
    *
    * @param  {string}   pathName    File location.
    * @param  {object}   [locals={}] Template variable context.
-   * @param  {Function} [fn]      Optional callback function.
+   * @param  {Function} [cb] Asyncronous callback function. If not provided, <var>compileFile</var> will run syncronously.
    * @return {string}             Rendered output.
    */
-  this.renderFile = function (pathName, locals, fn) {
+  this.renderFile = function (pathName, locals, cb) {
     var out;
-    try {
-      out = exports.compileFile(pathName)(locals);
-      if (fn) {
-        fn(null, out);
-        return;
-      }
-    } catch (e) {
-      if (fn) {
-        fn(e);
-        return;
-      }
-      throw e;
+    if (cb) {
+      exports.compileFile(pathName, {}, function (err, fn) {
+        if (err) {
+          cb(err);
+          return;
+        }
+        cb(null, fn(locals));
+      });
+      return;
     }
-    return out;
+
+    return exports.compileFile(pathName)(locals);
   };
 
   /**
@@ -561,9 +559,10 @@ exports.Swig = function (opts) {
    *
    * @param  {string} pathname  File location.
    * @param  {SwigOpts} [options={}] Swig options object.
+   * @param  {Function} [cb] Asyncronous callback function. If not provided, <var>compileFile</var> will run syncronously.
    * @return {function}         Renderable function with keys for parent, blocks, and tokens.
    */
-  this.compileFile = function (pathname, options) {
+  this.compileFile = function (pathname, options, cb) {
     var src, cached;
 
     if (!options) {
@@ -580,8 +579,18 @@ exports.Swig = function (opts) {
       return cached;
     }
 
-    src = fs.readFileSync(pathname, 'utf8');
+    if (cb) {
+      fs.readFile(pathname, 'utf8', function (err, src) {
+        if (err) {
+          cb(err);
+          return;
+        }
+        cb(err, self.compile(src, options));
+      });
+      return;
+    }
 
+    src = fs.readFileSync(pathname, 'utf8');
     return self.compile(src, options);
   };
 

tests/basic.test.js

@@ -1,5 +1,6 @@
 var swig = require('../lib/swig'),
   expect = require('expect.js'),
+  fs = require('fs'),
   _ = require('lodash'),
   Swig = swig.Swig;
 
@@ -12,7 +13,6 @@ function resetOptions() {
 }
 
 describe('options', function () {
-  var oDefaults;
   beforeEach(resetOptions);
   afterEach(resetOptions);
 
@@ -155,3 +155,49 @@ describe('separate instances', function () {
     expect(b.options.varControls[0]).to.equal('{{');
   });
 });
+
+describe('swig.compileFile', function () {
+  var test = __dirname + '/cases/extends_1.test.html';
+
+  beforeEach(resetOptions);
+  afterEach(resetOptions);
+
+  it('can run syncronously', function () {
+    expect(swig.compileFile(test)())
+      .to.be.ok();
+  });
+
+  it('can run asynchronously', function (done) {
+    expect(swig.compileFile(test, {}, function (err, fn) {
+      expect(fn).to.be.a(Function);
+      done();
+    }));
+  });
+});
+
+describe('swig.renderFile', function () {
+  var test = __dirname + '/cases/extends_1.test.html',
+    expectation = fs.readFileSync(test.replace('test.html', 'expectation.html'), 'utf8');
+
+  beforeEach(resetOptions);
+  afterEach(resetOptions);
+
+  it('can run syncronously', function () {
+    expect(swig.renderFile(test))
+      .to.equal(expectation);
+  });
+
+  it('can run asynchronously', function (done) {
+    expect(swig.renderFile(test, {}, function (err, fn) {
+      expect(fn).to.equal(expectation);
+      done();
+    }));
+  });
+
+  it('can use callbacks with errors', function (done) {
+    swig.renderFile(__dirname + '/cases/not-existing', {}, function (err, out) {
+      expect(err.errno).to.equal(34);
+      done();
+    });
+  });
+});

tests/templates.test.js

@@ -51,34 +51,4 @@ describe('Templates', function () {
       swig.compileFile(__dirname + '/cases-error/circular.test.html')();
     }).to.throwError(/Illegal circular extends of "[\w\/\._\-]+"\./);
   });
-
-  describe('renderFile', function () {
-    var extends_expectation = fs.readFileSync(__dirname + '/cases/extends_1.expectation.html', 'utf8'),
-      include_expectation = fs.readFileSync(__dirname + '/cases/include.expectation.html', 'utf8'),
-      opts = { locals: locals };
-
-    it('renders files immediately', function () {
-      expect(swig.renderFile(__dirname + '/cases/extends_1.test.html', opts)).to.equal(extends_expectation);
-    });
-
-    it('throws immediately with no callback', function () {
-      expect(function () {
-        swig.renderFile('foobar');
-      }).to.throwError();
-    });
-
-    it('can use callbacks', function (done) {
-      swig.renderFile(__dirname + '/cases/include.test.html', locals, function (err, out) {
-        expect(out).to.equal(include_expectation);
-        done();
-      });
-    });
-
-    it('can use callbacks with errors', function (done) {
-      swig.renderFile(__dirname + '/cases/not-existing', opts, function (err, out) {
-        expect(err.errno).to.equal(34);
-        done();
-      });
-    });
-  });
 });