EricDosReis / es-notes

Some notes about ECMAScript features, concepts, APIs, new releases ...

ECMAScript notes

• ES 2015
  • var, let and const
    • var allow redefinition
    • let and const redefinition is not allowed
    • var is not block scoped
    • let and const are block scoped
    • const reassignment is not allowed
    • Rules to follow when working with variables
  • Arrow Functions
    • Single parameter and implicit return
    • Multiples parameters
    • Returning an object literal
    • Using inside array methods like map, reduce or filter
    • Using with Rest Parameter
    • How this works with Arrow Functions
      • DOM listeners
      • call(), apply() and bind()
      • arguments is lexically scoped
      • new.target is lexically scoped
    • Constructors and generators
    • No prototype property
    • throw needs wrapping
  • Template Literals
    • Tagged Template
    • Tag Functions
  • Shorthand Properties
  • Default Parameters
    • Default values based on other parameters
  • New String Methods
    • String.prototype.startsWith()
    • String.prototype.endsWith()
    • String.prototype.includes()
    • String.prototype.repeat()
  • New Array Methods
    • Array.from()
    • Array.of()
    • Array.prototype.find() and Array.prototype.findIndex()
    • Array.prototype.fill()
  • Destructuring
    • Destructuring Object
    • Destructuring Array
    • Swap variables with Destructuring
    • Destructuring with Default Values
  • Spread Operator
    • Spread Operator with Functions
  • Rest/Gather Operator
  • Promises
    • Promise.all()
    • Promise.race()
  • Classes
    • Static Methods
    • Extends
  • Symbol
  • Iterables and Iterators
  • Generators
    • Generators with Asynchronous Flows
  • Proxy
  • Set
    • Array with unique values
  • WeakSet
  • Map
  • WeakMap
    • WeakSet, WeakMap and the Garbage Collector
• ES Modules
• ES 2016
  • Exponential Operator
  • Array.prototype.includes
• ES 2017
  • Async/Await
    • Advantages
    • Treating erros with Try/Catch
    • Async/Await with multiples Promises
  • String.prototype.padStart() and String.prototype.padEnd()
  • Object.entries()
  • Object.values()
  • Object.getOwnPropertyDescriptors()
  • Trailing Commas
• ES 2018
  • Rest/Spread Properties
    • Rest operator in object destructuring
    • The spread operator in object literals
    • Shallow cloning
    • Merge objects
  • RegExp named capture groups
    • Numbered capture groups
    • Named capure groups
    • replace() and named capture groups
  • RegExp Unicode property escapes
  • RegExp Lookbehind Assertions
  • s (dotAll) flag for regular expressions
  • Promise.prototype.finally()
• ES 2019