Webpack html-loader, include data-src image for lazy loading

Question

I'm using webpack with html-loader to create an assets folder inside my dist folder. But I'm trying to implement lazy loading on images by changing src attribute with a data-src link.

I found in the doc that you can specify others attribute, which is what I did.

rules: [
    {
        test: /\.html$/,
        use: {
            loader: "html-loader",
            options: {
                attributes: [':srcset',':data-srcset', 'img:data-src', 'img:src', 'audio:src', 'video:src', 'track:src', 'embed:src', 'source:src', 'input:src', 'object:data', 'script:src']
            }
        }
    },
    {
        test: /\.(svg|png|jpg|jpeg|gif)$/, // Ajouter les nouveaux types quand il y en a
        use: {
            loader: "file-loader",
            options: {
                name: "[name]-[hash].[ext]",
                outputPath: "assets",
                esModule: false
            }
        }
    }
]

<img data-src="./assets/image.jpg" alt="">

When I'm running webpack, my image isn't created in the dist folder.

I found others questions here and here about that but couldn't find a good answer.

Answer 1

After 1 day of research. Turns out you need to use attrs instead of attributes. The doc seems to be wrong... So you should have something like that.

test: /\.html$/,
use: {
    loader: "html-loader",
    options: {
        attrs: [':srcset',':data-srcset', 'img:data-src', 'img:src', 'audio:src', 'video:src', 'track:src', 'embed:src', 'source:src', 'input:src', 'object:data', 'script:src']
    }
}

Answer 2

The correct syntax for now (webpack 4) is as follows:

{
    test: /\.html$/i,
    use: {
        loader: 'html-loader',
        options: {
            sources: {
                list: [
                    "...", // important, to correctly handle the default tags like 'src'
                    {
                        tag: "img",
                        attribute: "data-src",
                        type: "src",
                    },
                ]
            }
        }
    }
}

You'll find a detailed description here: https://webpack.js.org/loaders/html-loader/#sources