I am using webpack with HtmlWebpackPlugin, html-loader and file-loader. I have a simple project structure in which I use no frameworks, but only typescript. Thus, I write my HTML code directly to index.html. I also use this HTML file as my template in HtmlWebpackPlugin.
As all websites do I need to put an image which refers to a PNG in my assets folder. file-loader should load the file correctly put the new filename inside the src tag but that is not what is happening. Instead, as the value of src tag, I have [object Module]. I assume the file-loader emits some object and it is represented like this when its .toString() method is run. However, I can see that file-loader has processed the file successfully and emitted with new name to the output path. I get no errors. Here is my webpack configuration and index.html.
const projectRoot = path.resolve(__dirname, '..');
{
entry: path.resolve(projectRoot, 'src', 'app.ts'),
mode: 'production',
output: {
path: path.resolve(projectRoot, 'dist'),
filename: 'app.bundle.js'
},
resolve: {
extensions: ['.ts', '.js']
},
module: {
rules: [
{
test: /\.html$/i,
use: 'html-loader'
},
{
test: /\.(eot|ttf|woff|woff2|svg|png)$/i,
use: 'file-loader'
},
{
test: /\.scss$/i,
use: [
{
loader: MiniCssExtractPlugin.loader,
options: {
hmr: false
}
},
{
loader: 'css-loader',
options: {
sourceMap: false
}
},
{
loader: 'sass-loader',
options: {
sourceMap: false
}
}
]
},
{
exclude: /node_modules/,
test: /\.ts$/,
use: 'ts-loader'
}
]
},
plugins: [
new CleanWebpackPlugin(),
new HtmlWebpackPlugin({
template: path.resolve(projectRoot, 'src', 'index.html')
}),
new MiniCssExtractPlugin({
filename: '[name].[hash].css',
chunkFilename: '[id].[hash].css',
ignoreOrder: false
})
]
};
index.html:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title></title>
</head>
<body class="dark">
<header>
<nav class="navigation">
<div class="left">
<img src="assets/logo.png" class="logo"> <!-- This logo is output as [object Module] -->
</div>
<div class="right">
</div>
</nav>
</header>
</body>
</html>
Project structure:
config/
webpack.config.js
dist/
src/
styles/
assets/
logo.png
index.html
app.ts
Edit My package.json dependencies:
"clean-webpack-plugin": "^3.0.0",
"css-loader": "^3.2.0",
"file-loader": "^5.0.2",
"html-webpack-plugin": "^3.2.0",
"mini-css-extract-plugin": "^0.8.0",
"node-sass": "^4.13.0",
"sass-loader": "^8.0.0",
"style-loader": "^1.0.0",
"ts-loader": "^6.2.1",
"typescript": "^3.7.2",
"webpack": "^4.41.2",
"webpack-cli": "^3.3.10",
"webpack-dev-server": "^3.9.0"
Per the file-loader docs:
By default, file-loader generates JS modules that use the ES modules syntax. There are some cases in which using ES modules is beneficial, like in the case of module concatenation and tree shaking.
It seems that webpack resolves ES module require() calls to an object that looks like this: {default: module}, instead of to the flattened module itself. This behavior is somewhat controversial and is discussed in this issue.
Therefore, to get your src attribute to resolve correctly, you need to be able to access the default property of the exported module. If you're using a framework, you should be able to do something like this:
<img src={require('assets/logo.png').default}/> <!-- React -->
<!-- OR -->
<img src="require('assets/logo.png').default"/> <!-- Vue -->
Alternatively, you can enable file-loader's CommonJS module syntax, which webpack will resolve directly to the module itself. Set esModule:false in your webpack config.
webpack.config.js:
{
test: /\.(png|jpe?g|gif)$/i,
use: [
{
loader: 'file-loader',
options: {
esModule: false,
},
},
],
},
@stellr42's suggested fix of esModule: false in your file-loader configuration is the best workaround at the current time.
However, this is actually a bug in html-loader which is being tracked here: https://github.com/webpack-contrib/html-loader/issues/203
It looks like ES Module support was added to file-loader, css-loader, and other friends, but html-loader was missed.
Once this bug is fixed, it will be better to remove esModule: false and simply upgrade html-loader, as ES Modules offer some minor benefits (as mentioned in the docs)
Alternatively, if (like me), you found this issue because you were having trouble loading an image from CSS (instead of from HTML), then the fix is just to upgrade css-loader, no need to disable ES Modules.
Just updated my file-loader to ^5.0.2 minutes ago.
I know esModule: false was the suggested fix but that did not work for me.
My fix was <img src={require('assets/logo.png').default}/> which was weird. First time using .default but it worked.