JavaScript

Data Structure Study in JS (Set)

Data Structure, JavaScript
  • Keywords

    unordered, unique elements, cannot be repeated, array with no repeated elements, no concept/order

Set in ECMA6

https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/Set

Set object allows storing unique values of any type. One can iterate through elements of a set in insertion order.

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new Set([iterable]);
  • Each value must be unique. Value equality will be checked.
  • NaN and undefined can also be stored in a Set.
  • NaN is considered the same with NaN. (Even though NaN !== NaN)
  • +0 and -0

Properties

  1. Set.length ( == 0)
  2. get Set[@@species] : constructor function that is used to create objects
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class MySet extends Set{
  // Overwrite Myset soecies to the parent Set constructor
  static get [Symbol.species]() { return Set; }
}
  1. Set.prototype : represents prototype for Set constructor. Allows addition to all Set objects.

Properties

1.Set.prototype.constructor : Returns function that created an instance’s prototype.

2.Set.prototype.size : Returns number of values in Set object.

Methods

1.Set.prototype.add(value) : appends a new element to the Set object and returns it.

2.Set.prototype.clear() : removes all elements from the Set object.

3.Set.prototype.delete(value) : Removes the element of value, returns what would have been returned by Set.prototype.has(value) previously. Set.prototype.has(value) will return false afterwards.

4.Set.prototype.entries() : Returns iterator object that contains an array of [value, value] for each element in the Set object, in insertion order.

5.Set.prototype.forEach(callbackFn[, thisArg]) : Calls callbackFn for each value in Set object, in insertion order. If an argument is provided, used as this value in each callback.

6.Set.prototype.values() : Returns new iterator object that contains values of each element in a set.

7.Set.prototype[@@iterator](): same with Set.prototype.values()

Instances

All Set instances inherit from Set.prototype.

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