Is the Javascript engine in this app running in strict mode by default?

Question

I have noticed several of the projects I have worked on seen to show behaviors associated with strict mode.
Does this app's Javascript engine run in strict mode by default?

Answer 1

function isStrictMode() {
try{var o={p:1,p:2};}catch(E){return true;}
return false;
}

console.log(isStrictMode());

var isStrict = (function() { return !this; })();

console.log(isStrict);