React Course1.0.0 beta

Chapter 0 · 10 lessons

JavaScript

All the JavaScript React needs: from variables to async and the patterns you meet everywhere in React.

JavaScript in general

0.1Variables, types and operatorsconst and let, numbers and text, type conversion, === vs. == and useful string methods.0.2Functions and closuresArrow functions, parameters, callbacks, functions returning functions, closures and pure functions.0.3ObjectsDot vs. square brackets, destructuring, spread, Object.entries and dynamic keys.0.4Arrays I: map, filter and friendsIndexes, map, filter, find, some, every, forEach and method chaining.0.5Arrays II: reduce, sorting and groupingreduce in depth, toSorted, Object.groupBy, Set, flatMap and the methods that change an array.0.6Conditions and logical operatorsTruthy and falsy, the ternary, &&, ||, ??, ?., switch and early return.0.7Asynchronous JavaScriptsetTimeout and the event loop, Promise, async/await, errors, Promise.all and fetch.0.8Modules and built-in toolsimport/export, JSON, Math, Date, Intl, localStorage and classes in a nutshell.

JavaScript for React

0.9References and immutabilityValue vs. reference, shallow copies, nested updates without mutation – and why React depends on it.0.10JS patterns you meet everywhere in ReactLists with map, conditions in JSX, functions in onClick, state updates and closures in components.