Question

According to this article

Adding “use strict” as the first statement¹ in your JavaScript code
will enforce Strict Mode over the entire

So why :

"use strict";
012; 

Doesn’t throw errors

while

(function () {
    "use strict";
    012; })();

does ? (Octal literals are not allowed in strict mode.)

John resig says nothing about it. he just says :

Simple. Toss this at the top of a program to enable it for the whole
script:

"use strict"; Or place it within a function to turn on strict mode
only within that context.

function imStrict(){ "use strict"; // … your code … }

edit :

edit #2.

I tested the code in console.(chrome). in jsbin sample – it is working. still , I dont understand why it behave different in console.

Answer 1

It does throw an error.

quentin@workstation:~ # cat > tmp/foo.js
"use strict";
012; 

quentin@workstation:~ # node tmp/foo.js

/users/quentin/tmp/foo.js:2
012; 
^^^

module.js:434
  var compiledWrapper = runInThisContext(wrapper, filename, true);
                        ^
SyntaxError: Octal literals are not allowed in strict mode.
    at Module._compile (module.js:434:25)
    at Object..js (module.js:464:10)
    at Module.load (module.js:353:31)
    at Function._load (module.js:311:12)
    at Array.0 (module.js:484:10)
    at EventEmitter._tickCallback (node.js:190:38)