A Set data structure allows to add data to a container, a collection of objects or primitive types (strings, numbers or booleans), and you can think of it as a Map where values are used as map keys, with the map value always being a boolean true.
Sets are a new object type with ES6 (ES2015) that allow creating collections of unique values. The values in a set can be either simple primitives like strings or integers as well as more complex object types like object literals or arrays.
Why ! Is false?
! evaluates to false because the reference is truthy.  can be converted to an number (0 in this case) which is falsey. Therefore: the condition passes as equal.
What is the use of set data structure?
Introduction. A set is a data structure that can store any number of unique values in any order you so wish. Set’s are different from arrays in the sense that they only allow non-repeated, unique values within them.
What is JSON format?
Map is a collection of keyed data items, just like an Object . But the main difference is that Map allows keys of any type. … map. set(key, value) – stores the value by the key.
Is a set an array?
Sets and arrays have several features in common. They both store a collection of values of the same type. … A set is unordered and each element can only appear once in a set. While an array can contain duplicate elements, each value contained in a set is unique.
The Set object lets you store unique values of any type, whether primitive values or object references.
- Union → returns a new Set which has all the elements from both set.
- Intersection→ returns a new Set which has common elements in both set.
- Difference → Set A — Set B will return elements from Set A which are not in Set B .
The map() method creates a new array with the results of calling a function for every array element. The map() method calls the provided function once for each element in an array, in order. map() does not execute the function for empty elements.