what is the type of result after merge operator？

[DYSDF]

At first I thought it was a normal object data, when i use push method, I found that I was wrong.

for example:

const path = require('path')
const merge = require('webpack-merge')
const HtmlWebpackPlugin = require('html-webpack-plugin');
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin

const conf1 = {
  entry: {
    page1: 'src/page1',
    page2: 'src/page2'
  },
  output: {
    path: path.resolve(__dirname, 'dist'),
    publicPath: '/'
  }
}

const conf2 = {
  entry: {
    page3: 'src/page3',
    page4: 'src/page4'
  },
  output: {
    path: path.resolve(__dirname, 'dist'),
    publicPath: '/'
  }
}

const enhance = {
  plugins: [
    new BundleAnalyzerPlugin({
      analyzerMode: 'server',
    })
  ]
}

const result1 = merge(conf1, enhance)
const result2 = merge(conf2, enhance)

console.log(result1.plugins.length)
console.log(result2.plugins.length)

the result is:

When I use the push method to add HtmlWebpackPlugin，the result has change.

const path = require('path')
const merge = require('webpack-merge')
const HtmlWebpackPlugin = require('html-webpack-plugin');
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin

const conf1 = {
  entry: {
    page1: 'src/page1',
    page2: 'src/page2'
  },
  output: {
    path: path.resolve(__dirname, 'dist'),
    publicPath: '/'
  }
}

const conf2 = {
  entry: {
    page3: 'src/page3',
    page4: 'src/page4'
  },
  output: {
    path: path.resolve(__dirname, 'dist'),
    publicPath: '/'
  }
}

const enhance = {
  plugins: [
    new BundleAnalyzerPlugin({
      analyzerMode: 'server',
    })
  ]
}

const result1 = merge(conf1, enhance)
const result2 = merge(conf2, enhance)

result1.plugins.push(
  new HtmlWebpackPlugin()
)

console.log(result1.plugins.length)
console.log(result2.plugins.length)

I have not operated another, but the plugins is changed.

when i use merge method, the result is correct.

const path = require('path')
const merge = require('webpack-merge')
const HtmlWebpackPlugin = require('html-webpack-plugin');
const BundleAnalyzerPlugin = require('webpack-bundle-analyzer').BundleAnalyzerPlugin

const conf1 = {
  entry: {
    page1: 'src/page1',
    page2: 'src/page2'
  },
  output: {
    path: path.resolve(__dirname, 'dist'),
    publicPath: '/'
  }
}

const conf2 = {
  entry: {
    page3: 'src/page3',
    page4: 'src/page4'
  },
  output: {
    path: path.resolve(__dirname, 'dist'),
    publicPath: '/'
  }
}

const enhance = {
  plugins: [
    new BundleAnalyzerPlugin({
      analyzerMode: 'server',
    })
  ]
}

let result1 = merge(conf1, enhance)
const result2 = merge(conf2, enhance)

result1 = merge(result1, {
  plugins: [
    new HtmlWebpackPlugin()
  ]
})

console.log(result1.plugins.length)
console.log(result2.plugins.length)

why?

[bebraw]

Thanks for the report. Resolved in 4.2.1. Sorry for the delay. Super busy year with work.