Syntax highlighting is incorrect for certain JavaScript use cases

Issue Summary

For certain use cases of JavaScript, the syntax highlighting that is used when displaying the source of .js files is incorrect.

Steps to Reproduce

1. Have a .js file with the following content

   public something(callback: callback, options?: ConsumerOptions): Promise<Consumer> {
   	console.info(`[${this.constructor.name}] Consumer creating.`);
   
   	this.consumer = Consumer.create({
   		...options,
   		queueUrl: await this.getUrl(),
   		handleMessage: message => {
   			if (message.Body){
   				message.Body = JSON.parse(message.Body);
   			}
   		}
   	})
   }
   

2. View the file in source view

Expected Results

The syntax is highlighted consistently, something like this way:

Actual Results

The syntax is highlighted incorrectly:

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available