Lodash examples for FE Guild

lodash_guild.js

_ = require("lodash");

var result;
var DATA = [
  {name: "Student One",
  id: 1,
  scores: [30, 50, 80]
  },
  {name: "Student Two",
  id: 2,
  scores: [85, 90, 82]
  },
  {name: "Student Three",
  id: 3,
  scores: [30, 40, 44]
  },
  {name: "Student Four",
  id: 4,
  scores: [24, 59, 34]
  },
  {name: "Student Five",
  id: 5,
  scores: [100, 97, 100]
  }
];


//////////////// FINDING ////////////////////////////

// for (var i = 0; i < DATA.length; i += 1) {
//   if (DATA[i].id === 2) {
//     result = DATA[i];
//     break;
//   }
// }

// result = _.find(DATA, function(e) {return e.id === 2;});

//////////////// FILTERING /////////////////////////

// result = [];
// for (var i = 0; i < DATA.length; i += 1) {
//   if (DATA[i].id > 2) {
//     result.push(DATA[i]);
//   }
// }

// var result = _.filter(DATA, function(e) {return e.id > 2;});


/////////////// REAL WORLD FILTERING ////////////////////

// var averageScore;
// result = [];
// for (var i = 0; i < DATA.length; i += 1) {
//   averageScore = 0;
//   for (var j = 0; j < DATA[i].scores.length; j += 1) {
//     averageScore += DATA[i].scores[j];
//   }
//   averageScore = averageScore / DATA[i].scores.length;
//   if (averageScore >= 50) {
//     result.push(DATA[i]);
//   }
// }

// result = _.filter(DATA, function(student) {
//   return (_.reduce(student.scores, function(total, score) {
//     return total + score;
//   }) / student.scores.length) >= 50;
// });

//////////////// DEFERRING ///////////////////////

// setTimeout(function(someDOMManipulation), 1);

// _.defer(someDOMManipulation);

// _.debounce(function, time)

//////////////// PICKING ///////////////////////////////

var student = {
  key: "123",
  name: "First Last",
  firstName: "First",
  lastName: "Last",
  middleName: "Middle",
  formattedFirstName: "First"
};

// result = {id: student.key};
// result.name = student.name;
// result.firstName = student.firstName;
// result.lastName = student.lastName;
// result.middleName = student.middleName;
// result.formattedFirstName = student.formattedFirstName;

// result = _.merge({id: student.key}, _.pick(student, ['name', 'firstName', 'lastName', 'middleName', 'formattedFirstName']));

//////////////// CHAINING ///////////////////////////////

// result = {};
// for (var i = 0; i < DATA.length; i++) {
//   var sum = 0;
//   for (var j = 0; j < DATA[i].scores.length; j++) {
//     sum += DATA[i].scores[j];
//   }
//   result[DATA[i].name] = sum / DATA[i].scores.length;
// }

// result = _(DATA)
//   .indexBy('name')
//   .mapValues(function(s) {return _.sum(s.scores) / s.scores.length})
//   .value();


console.log(result);