JavaScript Internals (521 Qs)•Part 2: Promises, Callbacks, Async & Strict Mode (54 - 103)
How do you declare strict mode
The strict mode is declared by adding "use strict"; to the beginning of a script or a function. If declared at the beginning of a script, it has global scope.
javascript
"use strict";
x = 3.14; // This will cause an error because x is not declared
and if you declare inside a function, it has local scope
javascript
x = 3.14; // This will not cause an error.
myFunction();
function myFunction() {
"use strict";
y = 3.14; // This will cause an error
}