DevTools failed to load SourceMap for webpack:///node_modules//....js.map HTTP error: status code 404, net::ERR_UNKNOWN_URL_SCHEME
WebpackGoogle Chrome-DevtoolsWebpack Problem Overview
I created a simple webpack based project to learn snabbdom. Everything was OK except that sourcemap failed loading:
I don't know whose issue(webpack, chrome) it is. Is there anyone who know it?
Reproduction steps:
git clone https://github.com/tomwang1013/snabbdom-test.git
npm install
npm run dev
Webpack Solutions
Solution 1 - Webpack
The source map you are trying to load is in node_modules and not part of webpack bundle. "If not extracted and processed into the source map of the webpack bundle, browsers may misinterpret source map data" ref. When app is loaded that causes "ERR_UNKNOWN_URL_SCHEME" in chrome dev tools console.
To process node_module source maps to webpack bundle, use source-map-loader loader. That will fix console warnings.
Add dependency to package.json:
"devDependencies": {
"source-map-loader": "^1.0.0",
...
}
Update webpack.config.js:
module: {
rules: [
{
test: /\.js$/,
enforce: 'pre',
use: ['source-map-loader'],
},
],
},
To generate source maps for snabbdom-test project in general you can use SourceMapDevToolPlugin.
Update webpack.config.js:
const { SourceMapDevToolPlugin } = require("webpack");
plugins: [
new SourceMapDevToolPlugin({
filename: "[file].map"
}),
...
],
Solution 2 - Webpack
Update webpack.config.js
module.exports = {
// ...
entry: {
"app": "src/app.js"
},
output: {
path: path.join(__dirname, 'dist'),
filename: "[name].js",
sourceMapFilename: "[name].js.map"
},
devtool: "source-map"
// ...
};
Detailed in https://blog.sentry.io/2018/10/18/4-reasons-why-your-source-maps-are-broken
Solution 3 - Webpack
devtool: "eval-cheap-source-map"
Add this to your webpack config and that's it.
Solution 4 - Webpack
Add devtool: 'eval-source-map' to top most level of webpack.config
Solution 5 - Webpack
If you want to just turn these off, you can use a webpack devtool option that ignores them. Detailed in my related question here
Solution 6 - Webpack
Add below line to your weback config
devtool: 'source-map ./src',
Solution 7 - Webpack
@Phương Nam's answer will solve this error but even after setting filename: "[name].js", webpack may warn us regarding the conflict of multiple assets emitting to the same filename.
To fix above warning we can use SourceMapDevToolPlugin.
> This plugin enables more fine grained control of source map > generation. It is also enabled automatically by certain settings of > the devtool configuration option.
The following code to replace the configuration option devtool: inline-source-map with an equivalent custom plugin configuration:
// ...
plugins: [
// ...
new webpack.SourceMapDevToolPlugin({})
// ...
],
devtool: false
// ...
More examples of SourceMapDevToolPlugin
Solution 8 - Webpack
If nothing helps, try to use different webpack devtool mode.
Related the project for me working good this modes:
devtool: 'inline-source-map'
or
devtool: 'eval-cheap-source-map'
or
devtool: 'eval-cheap-module-source-map'
or
devtool: 'inline-cheap-module-source-map'
Solution 9 - Webpack
If you're here and you're using Typescript, make sure you've got sourceMap: true in compilerOptions in your tsconfig.
Solution 10 - Webpack
Perhaps in each of those js files there is something like url commented:
/*# sourceMappingURL=dsggdgdg.fdgdfn.dfg.map */
remove that