AddCustomCodePlugin.js

module.exports = AddCustomCodePlugin

function AddCustomCodePlugin() {}

AddCustomCodePlugin.prototype.apply = function(compiler) {
	var self = this
	compiler.plugin("compilation", function(compilation) {
		compilation.mainTemplate.plugin("local-vars", self.localVars.bind(self)))
	})
}

AddCustomCodePlugin.prototype.localVars = function(source, chunk) {
	return source + [
		"// Add your javascript code here.",
		"console.log('inside webpack bootstrap');"
	].join("\n");
}