比較程序編程與函數編程的效能差異

f01.js

var i, j, people1, people2, person, sum = 0, people = [
  {
    "name": {
      "first": "Will",
      "last": "Huang"
    },
    "company": "MINIASP"
  },
  {
    "name": {
      "first": "James",
      "last": "Huang"
    },
    "company": "Coolrare"
  },
  {
    "name": {
      "first": "Jeff",
      "last": "Wu"
    },
    "company": "MINIASP"
  }
]

console.time('init');
for(i=0; i < 1000000; i++) {
  people1 = [];
  
  for(j=0; j<people.length;j++) {
    var person = people[j];
    if(person.name.last === 'Huang') { people1.push(person); }
  }
  
  people2 = []
  
  for(j=0; j<people1.length;j++) {
    person = people1[j];
    people2.push({
      name: person.name.first + ' ' + person.name.last,
      company: person.company
    });
  }
 
  for(j=0; j<people2.length;j++) {
    person = people2[j];
    sum = sum + person.company.length;
  }
}
console.timeEnd('init');

f02.js

var i, people = [
  {
    "name": {
      "first": "Will",
      "last": "Huang"
    },
    "company": "MINIASP"
  },
  {
    "name": {
      "first": "James",
      "last": "Huang"
    },
    "company": "Coolrare"
  },
  {
    "name": {
      "first": "Jeff",
      "last": "Wu"
    },
    "company": "MINIASP"
  }
]

console.time('init');
for(i=0; i < 1000000; i++) {
 people
    .filter(function(person) {
      return person.name.last === 'Huang';
    })
    .map(function(person) {
      return {
        name: person.name.first + ' ' + person.name.last,
        company: person.company
      };
    })
    .reduce(function(sum, person) {
        return sum + person.company.length;
    }, 0); 
}
console.timeEnd('init');