Questions coming from the book, "You don't know JS"
It is the transformation of data from one type to another in order to display on the screen or perform any operations needed. Coercion is called explicit when we use built-in functions to do it and implicit when it is done in the context of an expression where the values of different types must be of the same type for the expression to be evaluated.
Static typing also known as type enforcement is the characteristic of some programming languages (e.x. C, Java) where you have to define the type of values a variable will hold upon its definition. Such type of lagnuages are called strongly typed. JavaScript is not a strongly type language. JavaScript supports dynamic typing which is the exact oposite: variables can hold values of any type without any type enforcement.
No, JavaScript has only typed values. Variables are just simple containers for values.
As of ES6, constants can be defined by using the const keyword. In contrast to var, const can and will create block scope when used inside of a block.
Scope, techincally called lexical scope is basically a collection of variables as well as the rules for how those variables are accessed by name. A variable name has to be unique within the same scope -- there can't be two different a variables sitting right next to each other. But the same variable name a could appear in different scopes.
The built-in types in JavaScript are: string, number, boolean, null & undefined, object and symbol (as of ES6). The operator typeof can be used to query the type of a value whether stored on a variable/constant or being a literal value. So, typeof operator is always one of 7 string (always returns type as string) values.
A long-standing bug of JavaScript is where the typeof null returns "object". This will never be fixed because too much code in the web relies on the bug and thus fixing would cause a lot more bugs!
No, rather than being proper built-in types, these should be thought of more like subtypes -- specialized versions of the object type. But only arrays are detected as object when typeof is used. Functions are detected as function.
JavaScript evaluates as false only the following values: "" (empty string), 0, -0, NaN, null, undefined and false. All other non falsy values are evaluated as true.
The difference between == and === is usually characterized that == checks for value equality and === checks for both value and type equality. However, this is inaccurate. The proper way to characterize them is that == checks for value equality with coercion allowed, and === checks for value equality without allowing coercion; === is often called strict equality for this reason.
IIFE stands for Immediately Invoked Function Expressions.