Error with newer versions of node/webpack

[osotnikov]

Recently I've upgraded my angular, typescript, webpack and node. I assume the issue is node but I'm not sure. Something broke this plugin so I'm getting this error:

An unhandled exception occurred: Cannot add property main.js, object is not extensible

the fix is to make a copy of "assets" array because the original object is not extensible:

`module.exports = class Rename {
constructor(options) {
this.options = { ...options };
}

apply(compiler) {
compiler.hooks.emit.tap('Rename.emit', compilation => {
const { assets } = compilation;
const { originNameReg, targetName } = this.options;
const originFiles = Object.keys(assets).filter(fileName =>
new RegExp(originNameReg).test(fileName)
);

  originFiles.forEach(fileName => {
    let assetsCopy = Object.assign([], assets);
    assetsCopy[fileName.replace(originNameReg, targetName)] = assetsCopy[fileName];
    delete assetsCopy[fileName];
  });
});

}
};`