webpack/webpack-dev-server 2 throws `ERROR in json.js - Parenthesized pattern`

[aaronbeall]

Do you want to request a feature or report a bug?

Report an error. But it could be user error. :)

What is the current behavior?

When running webpack-dev-server I get the error:

ERROR in ./~/json3/lib/json3.js
Module parse failed: /node_modules/json3/lib/json3.js Parenthesized pattern (89:12)
You may need an appropriate loader to handle this file type.
|           if (stringifySupported) {
|             // A test function object with a custom `toJSON` method.
|             (value = function () {
|               return 1;
|             }).toJSON = value;
 @ ./~/sockjs-client/lib/main.js 7:12-28
 @ ./~/sockjs-client/lib/entry.js
 @ (webpack)-dev-server/client/socket.js
 @ (webpack)-dev-server/client?http://localhost:8080
 @ multi (webpack)-dev-server/client?http://localhost:8080 ./main.tsx

If the current behavior is a bug, please provide the steps to reproduce.

My configuration for a React + TypeScript project:

module.exports = {
    context: __dirname + "/src",
    entry: "./main.tsx",
    output: {
        path: __dirname + "/dist",
        filename: "bundle.js"
    },
    devServer: {
     contentBase: __dirname + "/src",
    },
    devtool: "source-map",
    resolve: {
        extensions: [".tsx", ".ts", ".js"]
    },
    module: {
        loaders: [
            {
                test: /\.tsx?$/,
                loader: "ts-loader",
                exclude: /node_modules/
            }
        ]
    }
}

This config works without problems using webpack-dev-server@1 (the only config difference being "" added to extensions: ["", ".tsx", ".ts", ".js"] ).

I am not using json3 directly in code anywhere.

What is the expected behavior?

No error.

Please mention your webpack and Operating System version.

• webpack/webpack-dev-server 2.2.1
• OSX 10.11.4

[melbourne2991]

Experiencing the same problem

[SpaceK33z]

Can you reproduce this without TypeScript? I didn't manage to reproduce it, but I don't know (and don't want to spend the time) to configure Typescript exactly to reproduce this. Note that if it only occurs with TypeScript, it doesn't belong here.

[SpaceK33z]

Try to change modules.loaders to module.rules.

[SpaceK33z]

If that doesn't work, checkout webpack/webpack#4184 (comment)

[yakovkhalinsky]

I can confirm that installing acorn 4.0.7 manually fixes the issue

[aaronbeall]

It seems to have been the acorn issue... I blew away node_modules and re-installed webpack@2 webpack-dev-server@2 and the problem no longer exists, when I look at the acorn package it is using 4.0.8 which apparently fixed the issue.