JavaScript arrays
JavaScript arrays and array methods
Learn JavaScript arrays and array methods with focused lessons on list data, map, filter, reduce, iterables, Map, Set, destructuring, object entries, and JSON data handling.
Array and collection lessons
Array basics
Store ordered values, access items by index, update lists, and understand how arrays represent repeated data.
Outcome: Represent lists such as todos, users, scores, products, and search results.
- JavaScript arrays
- array basics
- array index
Array methods
Use common array methods to add, remove, find, transform, sort, and combine list values.
Outcome: Choose the right array method instead of rewriting list logic manually.
- JavaScript array methods
- array methods
- find sort splice
Map, filter, and reduce
Transform lists, keep matching items, and accumulate totals or grouped data with the core functional array methods.
Outcome: Write expressive list transformations for real application data.
- map filter reduce
- JavaScript map
- JavaScript reduce
Iterables
Understand iterable objects, for..of loops, and how arrays connect to the wider JavaScript iteration protocol.
Outcome: Loop through arrays and iterable data structures consistently.
- JavaScript iterables
- for of loop
- iterator protocol
Map and Set collections
Use Map for key-value collections and Set for unique values when arrays are not the best data structure.
Outcome: Pick arrays, maps, or sets based on lookup, ordering, and uniqueness needs.
- JavaScript Map
- JavaScript Set
- unique values
WeakMap and WeakSet
Learn where weak collections help associate metadata with objects without preventing garbage collection.
Outcome: Recognize specialized collection use cases in advanced JavaScript code.
- WeakMap
- WeakSet
- object metadata
Object keys, values, and entries
Convert object data into array-friendly key, value, and entry lists for iteration and transformation.
Outcome: Bridge object records and array methods without losing readable code.
- Object.keys
- Object.values
- Object.entries
Destructuring assignment
Extract values from arrays and objects with destructuring patterns, defaults, rest syntax, and nested data.
Outcome: Read data from lists and objects with compact, intentional bindings.
- JavaScript destructuring
- array destructuring
- rest syntax
Date and time lists
Work with Date objects in arrays when sorting records, formatting timestamps, and comparing time-based data.
Outcome: Handle ordered records that include dates or timestamps.
- JavaScript Date
- sort dates
- date arrays
JSON and arrays
Serialize arrays and objects to JSON, parse API data, and prepare list data for browser storage or network responses.
Outcome: Move array-shaped data between JavaScript, APIs, and storage formats.
- JSON arrays
- JSON parse
- JSON stringify