you don't know JS

•  “==“ vs “==="
• Coercion
• Does not compare underlying values of functions, arrays, objects
• Values that are default falsy, everything is truthy
• “"
• 0, -0, NaN
• null
• undefined
• false
• Hoisting - concept where you call a function before it is created

var a = 2;
foo(); // works because \`foo()\` declaration is "hoisted"
function foo() {
    a = 3;
    console.log( a ); // 3
    var a; // declaration is "hoisted" to the top of \`foo()\`
}
console.log( a ); // 2

• Functions as a value

var foo = function() {
// ..
};
var x = function bar(){
// ..
};

The first function

• Strict mode prevents hoisting
• this refers to where the function is executed

function foo() {
    console.log( this.bar );
}

var bar = "global";
var obj1 = {
    bar: "obj1",
    foo: foo
};
var obj2 = {
    bar: "obj2"
};
// -------
foo(); //gloal
obj1.foo(); // "obj1"
foo.call( obj2 ); // "obj2"
new foo(); // undefined