How to load image files with webpack file-loader

Z时代
2024-01-10
分类：技术分享

I am using webpack to manage a reactjs project. I want to load images in javascript by webpack file-loader. Below is the webpack.config.js:

const webpack = require('webpack');
const path = require('path');
const NpmInstallPlugin = require('npm-install-webpack-plugin');
const PATHS = {
react: path.join(__dirname, 'node_modules/react/dist/react.min.js'),
app: path.join(__dirname, 'src'),
build: path.join(__dirname, './dist')
};
module.exports = {
entry: {
jsx: './app/index.jsx',
},
output: {
path: PATHS.build,
filename: 'app.bundle.js',
},
watch: true,
devtool: 'eval-source-map',
relativeUrls: true,
resolve: {
extensions: ['', '.js', '.jsx', '.css', '.less'],
modulesDirectories: ['node_modules'],
alias: {
normalize_css: __dirname + '/node_modules/normalize.css/normalize.css',
}
},
module: {
preLoaders: [
{
test: /.js$/,
loader: "source-map-loader"
},
],
loaders: [
{
test: /.html$/,
loader: 'file?name=[name].[ext]',
},
{
test: /.jsx?$/,
exclude: /node_modules/,
loader: 'babel-loader?presets=es2015',
},
{test: /.css$/, loader: 'style-loader!css-loader'},
{test: /.(jpe?g|png|gif|svg)$/i, loader: "file-loader?name=/public/icons/[name].[ext]"},
{
test: /.js$/,
exclude: /node_modules/,
loaders: ['babel-loader?presets=es2015']
}
]
},
plugins: [
new webpack.optimize.UglifyJsPlugin({
compress: {
warnings: false,
},
output: {
comments: false,
},
}),
new NpmInstallPlugin({
save: true // --save
}),
new webpack.DefinePlugin({
"process.env": {
NODE_ENV: JSON.stringify("production")
}
}),
],
devServer: {
colors: true,
contentBase: __dirname,
historyApiFallback: true,
hot: true,
inline: true,
port: 9091,
progress: true,
stats: {
cached: false
}
}
}

I use this line to load image files and copy them to dist/public/icons directory and keep the same file name.

{test: /.(jpe?g|png|gif|svg)$/i, loader: "file-loader?name=/public/icons/[name].[ext]"}

But I have two problems on using it. When I run webpack command, the image file was copied to dist/public/icons/ directory as expected. How, ver it was also copied to dist directory with this file name "df55075baa16f3827a57549950901e90.png".

Below is my project structure:

enter image description here

Another problem is that I use below code to import this image file but it couldn't show on the browser. If I am using url 'public/icons/imageview_item_normal.png' on the img tag, it works fine. How to use the object imported from the image file?

import React, {Component} from 'react';
import {render} from 'react-dom';
import img from 'file!../../public/icons/imageview_item_normal.png'
export default class MainComponent extends Component {
render() {
return (
<div style={styles.container}>
download
<img src={img}/>
</div>
)
}
}
const styles = {
container: {
width: '100%',
height: '100%',
}
}

Answer

Regarding problem #1

Once you have the file-loader configured in the webpack.config, whenever you use import/require it tests the path against all loaders, and in case there is a match it passes the contents through that loader. In your case, it matched

{
    test: /.(jpe?g|png|gif|svg)$/i, 
    loader: "file-loader?name=/public/icons/[name].[ext]"
}

and therefore you see the image emitted to

dist/public/icons/imageview_item_normal.png

which is the wanted behavior.

The reason you are also getting the hash file name, is because you are adding an additional inline file-loader. You are importing the image as:

'file!../../public/icons/imageview_item_normal.png'.

Prefixing with file!, passes the file into the file-loader again, and this time it doesn't have the name configuration.

So your import should really just be:

import img from '../../public/icons/imageview_item_normal.png'

Update

As noted by @cgatian, if you actually want to use an inline file-loader, ignoring the webpack global configuration, you can prefix the import with two exclamation marks (!!):

import '!!file!../../public/icons/imageview_item_normal.png'.

Regarding problem #2

After importing the png, the img variable only holds the path the file-loader "knows about", which is public/icons/[name].[ext] (aka "file-loader? name=/public/icons/[name].[ext]"). Your output dir "dist" is unknown.

You could solve this in two ways: