01 ES6.md

ECMAScript 2015 / ES6

Objectives

• Concatenate strings and variables with template strings
• Declare variables with only let and const
• Write anonymous functions with arrow functions
• Declare defaults to functions parameters

Resource

https://github.com/rogerwschmidt/es6-lesson-workspace

Practice

• Update the following code to use ES6 features:

  var winners = [ 'Otis Duncan', 'Melba Frank', 'Damon Adams' ]
  
  function printWinnersByPlace (people) {
    var first = winners[0]
    var rest = winners.slice(1)
    return 'In 1st place is ' + first + '! Followed up by ' + rest.join(' and ') + '.'
  }
  
  printWinnersByPlace(winners)

• Update the following code to be terser and use ES6 features:

  function orderBy (array, key, options) {
    options = options || {}
    
    // create a copy of the array to sort
    var toSort = array.slice()
  
    if (options.asc) {
      toSort.sort(function (a, b) {
        return a[key] > b[key] ? 1 : -1
      })
    }
  
    if (options.desc) {
      toSort.sort(function (a, b) {
        return a[key] < b[key] ? 1 : -1
      })
    }
  
    return toSort
  }
  
  const people = [
    { firstName: 'Dustin', lastName: 'French', age: 23 },
    { firstName: 'Norman', lastName: 'Sanders', age: 44 },
    { firstName: 'Jessica', lastName: 'Glover', age: 39 },
    { firstName: 'Alfred', lastName: 'Hicks', age: 31 }
  ]
  
  orderBy(people, 'lastName', { desc: true })