error Invalid regular expression: /(.*\\__fixtures__\\.*|node_modules[\\\]react[\\\]dist[\\\].*|website\\node_modules\\.*|heapCapture\\bundle\.js|.*\\__tests__\\.*)$/: Unterminated character class.

                                    To fix the Invalid Regular Expressing while running 

react-native start
Go to \node_modules\metro-config\src\defaults\blacklist.js
if metro-config not found
then, go to \node_modules\metro\src\blacklist.js

Replace the SharedBlacklist with the following

var sharedBlacklist = [
    /node_modules[\/\\]react[\/\\]dist[\/\\].*/,
    /website\/node_modules\/.*/,
    /heapCapture\/bundle\.js/,
    /.*\/__tests__\/.*/
];

                                    I don't have metro-config in my project, now what?
I have found that in pretty older project there is no metro-config in node_modules. If it is the case with you, then,

Go to node_modules/metro-bundler/src/blacklist.js

And do the same step as mentioned in other answers, i.e.

Replace

var sharedBlacklist = [
    /node_modules[/\\]react[/\\]dist[/\\].*/,
    /website\/node_modules\/.*/,
    /heapCapture\/bundle\.js/,
    /.*\/__tests__\/.*/
];
with

var sharedBlacklist = [
    /node_modules[\/\\]react[\/\\]dist[\/\\].*/,
    /website\/node_modules\/.*/,
    /heapCapture\/bundle\.js/,
    /.*\/__tests__\/.*/
];
P.S. I faced the same situation in a couple of projects so thought sharing it might help someone.

Edit

As per comment by @beltrone the file might also exist in,

node_modules\metro-config\src\defaults\blacklist.js