For those who were wondering what strong mode is, this is a post to the Strengthening JS group, which for discussion of &quot;strong mode and type system extensions that the V8 team is working on.&quot;<p>Strong mode is &quot;a new language mode (an extension of strict mode) that implements a stronger semantics by removing brittle or costly features.&quot;<p><a href="https:&#x2F;&#x2F;developers.google.com&#x2F;v8&#x2F;experiments" rel="nofollow">https:&#x2F;&#x2F;developers.google.com&#x2F;v8&#x2F;experiments</a><p>The conclusion is that &quot;we have reluctantly decided not to pursue strong mode further.&quot;