{"action":"created","issue":{"url":"https://api.github.com/repos/webpack/webpack/issues/1112","labels_url":"https://api.github.com/repos/webpack/webpack/issues/1112/labels{/name}","comments_url":"https://api.github.com/repos/webpack/webpack/issues/1112/comments","events_url":"https://api.github.com/repos/webpack/webpack/issues/1112/events","html_url":"https://github.com/webpack/webpack/issues/1112","id":80469659,"number":1112,"title":"Weird Error with UglifyJS Plugin","user":{"login":"vkbansal","id":5930351,"avatar_url":"https://avatars.githubusercontent.com/u/5930351?v=3","gravatar_id":"","url":"https://api.github.com/users/vkbansal","html_url":"https://github.com/vkbansal","followers_url":"https://api.github.com/users/vkbansal/followers","following_url":"https://api.github.com/users/vkbansal/following{/other_user}","gists_url":"https://api.github.com/users/vkbansal/gists{/gist_id}","starred_url":"https://api.github.com/users/vkbansal/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/vkbansal/subscriptions","organizations_url":"https://api.github.com/users/vkbansal/orgs","repos_url":"https://api.github.com/users/vkbansal/repos","events_url":"https://api.github.com/users/vkbansal/events{/privacy}","received_events_url":"https://api.github.com/users/vkbansal/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/webpack/webpack/labels/question","name":"question","color":"cc317c"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2015-05-25T09:38:49Z","updated_at":"2015-11-14T19:14:00Z","closed_at":null,"body":"I'm a recent convert to webpack.\r\nI have the following config file.\r\n```js\r\nvar webpack = require(\"webpack\"),\r\n    path = require(\"path\");\r\n\r\nvar hotloader = function(file) {\r\n    var loader = [\r\n        \"webpack-dev-server/client?http://localhost:3000\", \"webpack/hot/only-dev-server\"\r\n    ];\r\n\r\n    if (Array.isArray(file)) {\r\n        loader.concat(file);\r\n\r\n    } else {\r\n        loader.push(file);\r\n    }\r\n\r\n    return loader;\r\n};\r\n\r\nmodule.exports = {\r\n    entry: {\r\n        \"vendor\": [\r\n            \"react\",\r\n            \"alt\",\r\n            \"immutable\",\r\n        ],\r\n        \"app1\": hotloader(\"./src/app1.js\"),\r\n        \"app2\": hotloader(\"./src/app2.js\")\r\n    },\r\n    output: {\r\n        path: path.join(__dirname, \"dev\"),\r\n        filename: \"[name].js\",\r\n        sourceMapFileName: \"[name].js.map\",\r\n        publicPath: \"http://localhost:3000/dev/\"\r\n    },\r\n    module: {\r\n        loaders: [\r\n            {\r\n                test: /\\.js$/,\r\n                loaders: [\"react-hot\", \"babel?stage=0\"],\r\n                include: path.join(__dirname, \"src\")\r\n            }\r\n        ]\r\n    },\r\n    devtool: \"source-map\",\r\n    external: {\r\n        react: {\r\n            root: \"React\",\r\n            commonjs2: \"react\",\r\n            commonjs: \"react\",\r\n            amd: \"react\"\r\n        },\r\n        jquery: {\r\n            root: \"jQuery\",\r\n            commonjs2: \"jquery\",\r\n            commonjs: \"jquery\",\r\n            amd: \"jquery\"\r\n        }\r\n    },\r\n    plugins: [\r\n        new webpack.HotModuleReplacementPlugin(),\r\n        new webpack.NoErrorsPlugin(),\r\n        new webpack.optimize.OccurenceOrderPlugin(),\r\n        new webpack.DefinePlugin({\r\n            \"process.env\": {\r\n                \"NODE_ENV\": JSON.stringify(\"production\")\r\n            }\r\n        }),\r\n        new webpack.optimize.UglifyJsPlugin({\r\n            compressor: {\r\n                warnings: false\r\n            },\r\n            mangle: false\r\n        }),\r\n        new webpack.optimize.CommonsChunkPlugin({\r\n            name: \"vendor\",\r\n            filename: \"vendor.js\",\r\n            minChunks: Infinity\r\n        })\r\n    ]\r\n};\r\n```\r\n\r\nWhen I comment out the UglifyJS Plugin, the compiled code errors like `could not read 'Symbol()' of undefined`. Otherwise everything works fine\r\n\r\nThe error is thrown from a file from `alt` plugin."},"comment":{"url":"https://api.github.com/repos/webpack/webpack/issues/comments/156735844","html_url":"https://github.com/webpack/webpack/issues/1112#issuecomment-156735844","issue_url":"https://api.github.com/repos/webpack/webpack/issues/1112","id":156735844,"user":{"login":"bebraw","id":166921,"avatar_url":"https://avatars.githubusercontent.com/u/166921?v=3","gravatar_id":"","url":"https://api.github.com/users/bebraw","html_url":"https://github.com/bebraw","followers_url":"https://api.github.com/users/bebraw/followers","following_url":"https://api.github.com/users/bebraw/following{/other_user}","gists_url":"https://api.github.com/users/bebraw/gists{/gist_id}","starred_url":"https://api.github.com/users/bebraw/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/bebraw/subscriptions","organizations_url":"https://api.github.com/users/bebraw/orgs","repos_url":"https://api.github.com/users/bebraw/repos","events_url":"https://api.github.com/users/bebraw/events{/privacy}","received_events_url":"https://api.github.com/users/bebraw/received_events","type":"User","site_admin":false},"created_at":"2015-11-14T19:14:00Z","updated_at":"2015-11-14T19:14:00Z","body":"@vkbansal Can you try with the current version?"}}