Added tests for Promise/async support in renderFile

mde · Jan 6, 2018 · 7c77ceb · 7c77ceb
1 parent c04ec96
commit 7c77ceb
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Showing 2 changed files with 58 additions and 3 deletions.
diff --git a/lib/ejs.js b/lib/ejs.js
@@ -93,6 +93,16 @@ exports.fileLoader = fs.readFileSync;
 
 exports.localsName = _DEFAULT_LOCALS_NAME;
 
+/**
+ * Promise implementation -- defaults to the native implementation if available
+ * This is mostly just for testability
+ *
+ * @type {Function}
+ * @public
+ */
+
+exports.promiseImpl = (new Function('return this;'))().Promise;
+
 /**
  * Get the path to the included file from the parent file path and the
  * specified path.
@@ -221,8 +231,8 @@ function handleCache(options, template) {
 function tryHandleCache(options, data, cb) {
   var result;
   if (!cb) {
-    if (typeof Promise == 'function') {
-      return new Promise(function (resolve, reject) { // eslint-disable-line no-undef
+    if (typeof exports.promiseImpl == 'function') {
+      return new exports.promiseImpl(function (resolve, reject) {
         try {
           result = handleCache(options)(data);
           resolve(result);

diff --git a/test/ejs.js b/test/ejs.js
@@ -292,7 +292,7 @@ suite('ejs.render(str, data, opts)', function () {
 
 });
 
-suite('ejs.renderFile(path, [data], [options], fn)', function () {
+suite('ejs.renderFile(path, [data], [options], [fn])', function () {
   test('render a file', function(done) {
     ejs.renderFile('test/fixtures/para.ejs', function(err, html) {
       if (err) {
@@ -303,6 +303,51 @@ suite('ejs.renderFile(path, [data], [options], fn)', function () {
     });
   });
 
+  test('Promise support', function(done) {
+    var AsyncCtor;
+    var func;
+    function checkResult(html) {
+      assert.equal(html, '<p>hey</p>\n');
+    }
+    // Environments without Promise support -- should throw
+    // when no callback provided
+    function checkNoPromise() {
+      delete ejs.promiseImpl;
+      assert.throws(function () {
+        ejs.renderFile('test/fixtures/para.ejs');
+      });
+      ejs.promiseImpl = global.Promise;
+      done();
+    }
+
+    // Check for async/await support -- have to use eval for check because
+    // envs without async will break at parsing step
+    try {
+      eval('AsyncCtor = (async function () {}).constructor;');
+    }
+    catch (e) {
+      // No-op
+    }
+
+    // Both async and Promise -- in both cases, also check the call
+    // correctly throws in non-Promise envs if no callback provided
+    // -------------------
+    // Async support -- have to use eval for constructing async func for
+    // same reasons as above
+    if (AsyncCtor) {
+      func = new AsyncCtor('ejs', 'checkResult', 'checkNoPromise',
+        "let res = await ejs.renderFile('test/fixtures/para.ejs'); checkResult(res); checkNoPromise();");
+      func(ejs, checkResult, checkNoPromise);
+    }
+    // Ordinary Promise support
+    else {
+      ejs.renderFile('test/fixtures/para.ejs').then(function (res) {
+        checkResult(res);
+        checkNoPromise();
+      });
+    }
+  });
+
   test('accept locals', function(done) {
     var data =  {name: 'fonebone'};
     var options = {delimiter: '$'};