A weakmap is a collection of key value pairs, in which the key must always be an object. A WeakMap is a map (dictionary) where the keys are weak - that is, if all references to the key are lost and there are no more references to the value - the value can be garbage collected.

Padding is included within the click region and background color/image, but margin is not. Vertical margins auto collapse, but paddings do not. Consider two elements, one above the other. If both have a padding of 1em, they will be 2ems apart. However if both have a margin of 1em, the margin will auto collapse, resulting in them being only 1em apart.

string, number, boolean, null, undefined, symbol, Bigint,

Design patterns are reusable solutions to commonly occurring problems in software design.

Referential equality vs structural equality? Referential equality of two objects means that they both reference the exact same object in memory. ie they use the same reference. Structural equality means they both objects have the same value.

Lexical scope is the definition area of an expression. ie the place in which the item was created. The place an item gets invoked, or called, is not necessarily the items lexical scope. Instead an items definition space is its lexical scope. Lexical scope refers to setting the scope, or range of functionality, of a variable. Lexical scope means that in a nested group of functions, the inner functions have access to the variables and other resources of their parent scope. This means that the child functions are lexically bound to the execution context of their parents. Every time the javascript engine creates an execution context to execute the function, or global code, it also creates a new lexical environment to store the variables defined in that function during the execution of that function. In lexical scope a child can access its parent scope and global scope, but a parent cannot access the child scope. CODE>>BLOCK>>FUNCTION>>GLOBAL Lexical scope does not care where the function is invoked.

Minimum viable product.

ESlint. A linter is a tool that analyses source code to flag programming errors, bugs, stylistic errors etc.