guifromrio

var approvedStudents = _.filter(students, isApproved)
_.map(approvedStudents, function (s) { return s.name })
// ["John", "Luke", "Mark"]

guifromrio

var students = [
  { name: "John", grades: [7.0, 6.9, 8.0], class: "A" },
  { name: "Paul", grades: [5.0, 8.7, 3.7], class: "A" },
  { name: "Luke", grades: [9.0, 8.2, 6.2], class: "B" },
  { name: "Mark", grades: [6.0, 9.0, 8.4], class: "B" }
];

var sum = function (numbers) { return _.reduce(numbers, function (sum, n) { return sum + n }, 0) }
var average = function (numbers) { return sum(numbers) / numbers.length }
var isApproved = function (student) { return average(student.grades) >= 7 }

guifromrio

import React from 'react'

// https://github.com/gaearon/babel-plugin-react-transform/issues/57
export default function wrapFunctionalComponent (fc) {
  return React.createClass({
    displayName: fc.Name,

    render() {
      return fc.apply(null, this.props)
    }

guifromrio

var array = [{name: "Foo", points: 1}, {name: "Bar", points: 3}];
var initial = 0;
var totalPoints = function (result, player) {
  return result + player.points;
};
var total = _.reduce(array, totalPoints, initial);
console.log(total) // 4

guifromrio

var array = [{name: "Foo", points: 1}, {name: "Bar", points: 3}];
var increasePoints = function (player) {
  return {name: player.name, points: player.points + 1};
};
var newArray = _.map(array, increasePoints);
console.log(newArray); // [{name: "Foo", points: 2}, {name: "Bar", points: 4}]

guifromrio

var array = [{name: "Foo", points: 1}, {name: "Bar", points: 3}];
var increasePoints = function (player) {
  return {name: player.name, points: player.points + 1};
};
var newArray = [];
_.each(array, function (player) { 
  newArray.push(increasePoints(player));
});
// array is undisturbed! a little clunky, though...

guifromrio

var array = [{name: "Foo", points: 1}, {name: "Bar", points: 3}];
var increasePoints = function (player) { 
  player.points++;
};
_.each(array, increasePoints); // MAGIC!

guifromrio

var array = [{name: "Foo", points: 1}, {name: "Bar", points: 3}];
var increasePoints = function (player) { 
  player.points++;
};
var i;
for (i = 0; i < array.length; i++) {
  increasePoints(array[i]);
}

guifromrio

var array = [{name: "Foo", points: 1}, {name: "Bar", points: 3}];
var value, i;
for (i = 0; i < array.length; i++) {
  value = array[i];
  value.points++;
}
console.log(array) // [{name: "Foo", points: 2}, {name: "Bar", points: 4}]

guifromrio

var CommentList = React.createClass({
  render: function() {
    var commentNodes = this.props.data.map(function (comment) {
      return (
        <Comment author={comment.author}>
          {comment.text}
        </Comment>
      );
    });
    return (