add support for before callback

Author: toddw

AUTHORS.txt

@@ -3,3 +3,4 @@ Authors ordered by first contribution.
 Andres Morey <[email protected]>
 revyh https://github.com/revyh
 Ryan Burke https://github.com/codeburke
+Todd Williams https://github.com/toddw

README.md

@@ -126,6 +126,14 @@ Note: LoadJS treats empty CSS files as load failures in IE (to get around lack o
   });
   ```
 
+1. Execute a callback before script tags is embedded
+
+  ```javascript
+  loadjs(['/path/to/foo.js', '/path/to/bar.js'], {
+    before: function(path, scriptEl) { /* called for each script node before embedded */ }
+  });
+  ```
+
 1. Execute a callback after bundle finishes loading
 
   ```javascript

dist/loadjs.js

@@ -84,6 +84,7 @@ function loadFile(path, callbackFn, args, numTries) {
   var doc = document,
       async = args.async,
       maxTries = (args.numRetries || 0) + 1,
+      beforeCallbackFn = (args.before || devnull),
       isCss,
       e;
 
@@ -132,6 +133,9 @@ function loadFile(path, callbackFn, args, numTries) {
     // execute callback
     callbackFn(path, result, ev.defaultPrevented);
   };
+
+  // execute before callback
+  beforeCallbackFn(path, e);
 
   // add to document
   doc.head.appendChild(e);

dist/loadjs.min.js

@@ -92,6 +92,7 @@ function loadFile(path, callbackFn, args, numTries) {
   var doc = document,
       async = args.async,
       maxTries = (args.numRetries || 0) + 1,
+      beforeCallbackFn = (args.before || devnull),
       isCss,
       e;
 
@@ -140,6 +141,9 @@ function loadFile(path, callbackFn, args, numTries) {
     // execute callback
     callbackFn(path, result, ev.defaultPrevented);
   };
+
+  // execute before callback
+  beforeCallbackFn(path, e);
 
   // add to document
   doc.head.appendChild(e);

dist/loadjs.umd.js

@@ -83,6 +83,7 @@ function loadFile(path, callbackFn, args, numTries) {
   var doc = document,
       async = args.async,
       maxTries = (args.numRetries || 0) + 1,
+      beforeCallbackFn = (args.before || devnull),
       isCss,
       e;
 
@@ -131,6 +132,9 @@ function loadFile(path, callbackFn, args, numTries) {
     // execute callback
     callbackFn(path, result, ev.defaultPrevented);
   };
+
+  // execute before callback
+  beforeCallbackFn(path, e);
 
   // add to document
   doc.head.appendChild(e);

src/loadjs.js

@@ -84,6 +84,7 @@ function loadFile(path, callbackFn, args, numTries) {
   var doc = document,
       async = args.async,
       maxTries = (args.numRetries || 0) + 1,
+      beforeCallbackFn = (args.before || devnull),
       isCss,
       e;
 
@@ -132,6 +133,9 @@ function loadFile(path, callbackFn, args, numTries) {
     // execute callback
     callbackFn(path, result, ev.defaultPrevented);
   };
+
+  // execute before callback
+  beforeCallbackFn(path, e);
 
   // add to document
   doc.head.appendChild(e);

test/assets/loadjs/loadjs.js

@@ -47,6 +47,34 @@ describe('LoadJS tests', function() {
         }
       });
     });
+
+
+    it('should call before callback before embedding into document', function(done) {
+      var scriptTags = [];
+
+      loadjs(['assets/file1.js', 'assets/file2.js'], {
+        before: function(path, el) {
+          scriptTags.push({
+            path: path,
+            el: el
+          });
+
+          // add cross origin script for file2
+          if (path === 'assets/file2.js') {
+            el.crossOrigin = 'anonymous';
+          }
+        },
+        success: function () {
+          assert.equal(scriptTags[0].path, 'assets/file1.js');
+          assert.equal(scriptTags[1].path, 'assets/file2.js');
+
+          assert.equal(scriptTags[0].el.crossOrigin, undefined);
+          assert.equal(scriptTags[1].el.crossOrigin, 'anonymous');
+
+          done();
+        }
+      });
+    });
 
 
     it('should call success callback on two valid paths', function(done) {