Test new features in javascript

es_next.js

function printArguments(target, name, descriptor) {
  let oldFunction = descriptor.value
  descriptor.value = function () {
    console.log(`start ${name} with arguments`, arguments)
    oldFunction.apply(target, arguments)
    console.log(`end function ${name}`)

  }
  return descriptor
}

export default class Example {
  // transform-async-generator-functions
  count = 0
  async getPosts() {
    const response = await fetch("https://jsonplaceholder.typicode.com/posts")
    const posts    = await response.json()
    console.log(posts) // async function
  }
  // transform-object-rest-spread
  mergeObject() {
    const objectDefault = { a: 0, b: 2 }
    const object = { ...objectDefault, b: 1, c: 3 }
    console.log("objectDefault", objectDefault) // { a: 0, b: 2 }
    console.log("object", object) // { a: 0, b: 1, c:3 }
  }
  // transform-decorators-legacy
  @printArguments
  sum(a, b){
    console.log(a + b)
  }
  // transform-class-properties
  incrementCount = () => {
    this.count++
    console.log("incrementCount", this.count)
  }
}


// Auto Run
const example = new Example

example.getPosts()
example.mergeObject()
example.sum(1, 1)
example.incrementCount()