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Learning JavaScript Data Structures and Algorithms - Third Edition
book

Learning JavaScript Data Structures and Algorithms - Third Edition

by Loiane Avancini
April 2018
Beginner to intermediate content levelBeginner to intermediate
426 pages
10h 19m
English
Packt Publishing
Content preview from Learning JavaScript Data Structures and Algorithms - Third Edition

The ES2015 WeakMap and WeakSet classes

Along with the two new data structures Set and Map, ES2015 also introduced a weak type version of these classes: WeakMap and WeakSet.

Basically, the only difference between the Map or Set classes and their weak versions are:

  • The WeakSet or WeakMap classes do not have the entries, keys, and values methods
  • It is only possible to use objects as keys

The reason for creating and using these two classes is performance-related. Since WeakSet and WeakMap are weakly typed (using the object as a key), there is no strong reference to the keys. This behavior allows the JavaScript garbage collector to clean an entire entry from the map or set.

Another advantage of the weak versions is we can only retrieve a value ...

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Learning JavaScript Data Structures and Algorithms

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Publisher Resources

ISBN: 9781788623872Supplemental Content