title: "Object doesn't support property or method 'find'" in IE11 with Babel and Webpack
body: <p>I'm getting some strange behavior in IE11 with use of Webpack and Babel. Currently, the issue is occurring is the following error message:</p>
  
  <p><code>SCRIPT438: Object doesn't support property or method 'find'</code></p>
  
  <p>This only occurs in Internet Explorer, and strangely enough doesn't occur when running the code locally, only when it has been published.</p>
  
  <pre><code>const getColumnByName = (columns, columnName) =&gt; {   
      return columns.find((col) =&gt; col.Name === columnName);
  }
  </code></pre>
  
  <p>Through the use of breakpoints, I can see that the code calls <code>columns.find</code> with an empty array 3 times, before it is passed an array of Objects. It is only on that 4th time that the error is thrown. In the IE console, I can run the following lines of code inside the above function to try to isolate the issue further.</p>
  
  <pre><code>Array.isArray(columns)
  #=&gt; true
  
  Array.prototype.find
  #=&gt; function (predicate) { ...
  
  [1,2,3].find(function(el){return el === 2})
  #=&gt; 2
  
  columns.length
  #=&gt; 17
  
  columns.find(function(e){return true})
  #=&gt; Object doesn't support property or method 'find'
  </code></pre>
  
  <p>All very strange to me.</p>
  
  <p>Below is my webpack.config file, incase that helps.</p>
  
  <pre><code>/// &lt;binding ProjectOpened='Watch - Development' /&gt;
  
  module.exports = {
    entry: [
      'babel-polyfill',
      './Scripts/App.js',
      ],
    output: {
      filename: 'Scripts/ReactBundle/bundle.js'
    },
    resolve: {
      extensions: ['.Webpack.js', '.web.js', '.js', '.jsx'],
      mainFields: ["main"]
    },
    module: {
        rules: [
          {
              test: /\.css$/,
              use: [ 'style-loader', 'css-loader' ]
          },
          {
              test: /\.js$/,
              exclude: /(node_modules|bower_components)/,
              loader: 'babel-loader',               
              query:
                    {
                        presets: ['react', 'es2017', 'es2015', 'stage-2'],
                        plugins: ['transform-class-properties']
                    }
          },
        ]
    },  
  }
  </code></pre>
  
  <p>Thanks in advance for any help or input.</p>