Fix for nolanlawson#7: Not as optimized for Webpack as it could be. Adds ability to wrap functions that are elements of an array literal in an argument list

Author: aickin

lib/index.js

@@ -21,15 +21,16 @@ function optimizeJs (jsString, opts) {
     var postChar = jsString.charAt(node.end)
     var postPostChar = jsString.charAt(node.end + 1)
 
-    // assuming this node is an argument to a function, return true if it itself
-    // is already padded with parentheses
+    // assuming this node is an argument to a function or an element in an array,
+    // return true if it itself is already padded with parentheses
     function isPaddedArgument (node) {
-      var idx = node.parentNode.arguments.indexOf(node)
+      var parentArray = node.parentNode.arguments ? node.parentNode.arguments : node.parentNode.elements
+      var idx = parentArray.indexOf(node)
       if (idx === 0) { // first arg
         if (prePreChar === '(' && preChar === '(' && postChar === ')') { // already padded
           return true
         }
-      } else if (idx === node.parentNode.arguments.length - 1) { // last arg
+      } else if (idx === parentArray.length - 1) { // last arg
         if (preChar === '(' && postChar === ')' && postPostChar === ')') { // already padded
           return true
         }
@@ -41,24 +42,48 @@ function optimizeJs (jsString, opts) {
       return false
     }
 
-    if (node.parentNode && node.parentNode.type === 'CallExpression') {
-      // this function is getting called itself or
-      // it is getting passed in to another call expression
-      // the else statement is strictly never hit, but I think the code is easier to read this way
-      /* istanbul ignore else */
-      if (node.parentNode.arguments.length && node.parentNode.arguments.indexOf(node) !== -1) {
-        // function passed in to another function. these are almost _always_ executed, e.g.
-        // UMD bundles, Browserify bundles, Node-style errbacks, Promise then()s and catch()s, etc.
-        if (!isPaddedArgument(node)) { // don't double-pad
-          magicString = magicString.insertLeft(node.start, '(')
-            .insertRight(node.end, ')')
-        }
-      } else if (node.parentNode.callee === node) {
-        // this function is getting immediately invoked, e.g. function(){}()
-        if (preChar !== '(') {
-          magicString.insertLeft(node.start, '(')
-            .insertRight(node.end, ')')
-        }
+    function isCallExpression (node) {
+      return node && node.type === 'CallExpression'
+    }
+
+    function isArrayExpression (node) {
+      return node && node.type === 'ArrayExpression'
+    }
+
+    // returns true iff node is an argument to a function call expression.
+    function isArgumentToFunctionCall (node) {
+      return isCallExpression(node.parentNode) &&
+        node.parentNode.arguments.length &&
+        node.parentNode.arguments.indexOf(node) !== -1
+    }
+
+    // returns true iff node is an element of an array literal which is in turn
+    // an argument to a function call expression.
+    function isElementOfArrayArgumentToFunctionCall (node) {
+      return isArrayExpression(node.parentNode) &&
+        node.parentNode.elements.indexOf(node) !== -1 &&
+        isArgumentToFunctionCall(node.parentNode)
+    }
+
+    // returns true iff node is an IIFE.
+    function isIIFE (node) {
+      return isCallExpression(node.parentNode) &&
+        node.parentNode.callee === node
+    }
+
+    if (isArgumentToFunctionCall(node) || isElementOfArrayArgumentToFunctionCall(node)) {
+      // function passed in to another function, either as an argument, or as an element
+      // of an array argument. these are almost _always_ executed, e.g. webpack bundles,
+      // UMD bundles, Browserify bundles, Node-style errbacks, Promise then()s and catch()s, etc.
+      if (!isPaddedArgument(node)) { // don't double-pad
+        magicString = magicString.insertLeft(node.start, '(')
+          .insertRight(node.end, ')')
+      }
+    } else if (isIIFE(node)) {
+      // this function is getting immediately invoked, e.g. function(){}()
+      if (preChar !== '(') {
+        magicString.insertLeft(node.start, '(')
+          .insertRight(node.end, ')')
       }
     }
   }

test/cases/webpack-style-multi-element/input.js

@@ -0,0 +1,9 @@
+!function(o){
+  return o[0]();
+}([function(o,r,t){
+  console.log("webpack style element 0");
+},function(o,r,t){
+  console.log("webpack style element 1");
+},function(o,r,t){
+  console.log("webpack style element 2");
+}]);

test/cases/webpack-style-multi-element/output.js

@@ -0,0 +1,9 @@
+!(function(o){
+  return o[0]();
+})([(function(o,r,t){
+  console.log("webpack style element 0");
+}),(function(o,r,t){
+  console.log("webpack style element 1");
+}),(function(o,r,t){
+  console.log("webpack style element 2");
+})]);

test/cases/webpack-style-one-element/input.js

@@ -0,0 +1,5 @@
+!function(o){
+  return o[0]();
+}([function(o,r,t){
+  console.log("webpack style!");
+}]);

test/cases/webpack-style-one-element/output.js

@@ -0,0 +1,5 @@
+!(function(o){
+  return o[0]();
+})([(function(o,r,t){
+  console.log("webpack style!");
+})]);