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// implement map// implement map
function map(array, cb) {
let i;
let mapped = [];
for (i = 0; i < array.length; i += 1) {
total.push(cb(array[i]));
}
return mapped;
}
// test out the map function
const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
const doubled = map(arr, item => {
return item * 2;
});
console.log(doubled);
// implement filter function
function filter(array, cb) {
let i;
let filtered = [];
for (i = 0; i < array.length; i += 1) {
if (cb(array[i])) {
filtered.push(array[i]);
}
}
return filtered;
}
// test out the filter function
const arr2 = [
{ name: "Bently", age: 2 },
{ name: "Zaphy", age: 12 },
{ name: "Domino", age: 11 }
];
const ageGreaterThanFive = filter(arr2, r => {
return r.age > 5;
});
console.log(ageGreaterThanFive);
/* output
2, 4, 6, 8, 10, 12, 14, 16, 18, 20 ]
[ { name: 'Zaphy', age: 12 }, { name: 'Domino', age: 11 } ]
*/
// implement reduce function
function reduce(array, cb, accumulator) {
let i;
for (i = 0; i < array.length; i += 1) {
if (!accumulator) {
accumulator = array[i];
}
accumulator = cb(accumulator, array[i]);
}
return accumulator;
}
const arr3 = [1, 2, 3, 4];
const arr4 = [
{ key1: "test1", key2: "test2" },
{ key1: "test3", key2: "test4" },
{ key1: "test5", key2: "test6" },
{ key1: "test7", key2: "test8" },
{ key1: "test9", key2: "test10" },
{ key1: "test11", key2: "test12" },
{ key1: "test13", key2: "test14" },
{ key1: "test15", key2: "test16" }
];
// test out the method on simple numbers and objects.
const summed = reduce(arr3, num => {
return 2 * num;
});
console.log(summed);
combinedObjects = reduce(
arr4,
(acc, obj) => {
acc.push(obj.key1);
return acc;
},
[]
);
console.log(combinedObjects);
/* output
[ 'test1',
'test3',
'test5',
'test7',
'test9',
'test11',
'test13',
'test15' ]
*/
function multiplyBy2(arr, num) {
const newArr = [];
for (let i = 0; i < arr.length; i += 1) {
newArr.push(arr[i] * num);
}
return newArr;
}
console.log(multiplyBy2([1, 2, 3, 4, 5, 6], 2));
const heroes = [
{
superhero: "Batman",
publisher: "DC Comics",
alter_ego: "Bruce Wayne",
first_appearance: "Detective Comics #27",
characters: "Bruce Wayne"
},
{
superhero: "Superman",
publisher: "DC Comics",
alter_ego: "Kal-El",
first_appearance: "Action Comics #1",
characters: "Kal-El"
},
{
superhero: "Flash",
publisher: "DC Comics",
alter_ego: "Jay Garrick",
first_appearance: "Flash Comics #1",
characters: "Jay Garrick, Barry Allen, Wally West, Bart Allen"
},
{
superhero: "Green Lantern",
publisher: "DC Comics",
alter_ego: "Alan Scott",
first_appearance: "All-American Comics #16",
characters:
"Alan Scott, Hal Jordan, Guy Gardner, John Stewart, Kyle Raynor, Jade, Sinestro, Simon Baz"
},
{
superhero: "Green Arrow",
publisher: "DC Comics",
alter_ego: "Oliver Queen",
first_appearance: "More Fun Comics #73",
characters: "Oliver Queen"
},
{
superhero: "Wonder Woman",
publisher: "DC Comics",
alter_ego: "Princess Diana",
first_appearance: "All Star Comics #8",
characters: "Princess Diana"
},
{
superhero: "Martian Manhunter",
publisher: "DC Comics",
alter_ego: "J'onn J'onzz",
first_appearance: "Detective Comics #225",
characters: "Martian Manhunter"
},
{
superhero: "Robin/Nightwing",
publisher: "DC Comics",
alter_ego: "Dick Grayson",
first_appearance: "Detective Comics #38",
characters: "Dick Grayson"
},
{
superhero: "Blue Beetle",
publisher: "DC Comics",
alter_ego: "Dan Garret",
first_appearance: "Mystery Men Comics #1",
characters: "Dan Garret, Ted Kord, Jaime Reyes"
},
{
superhero: "Black Canary",
publisher: "DC Comics",
alter_ego: "Dinah Drake",
first_appearance: "Flash Comics #86",
characters: "Dinah Drake, Dinah Lance"
},
{
superhero: "Spider Man",
publisher: "Marvel Comics",
alter_ego: "Peter Parker",
first_appearance: "Amazing Fantasy #15",
characters: "Peter Parker"
},
{
superhero: "Captain America",
publisher: "Marvel Comics",
alter_ego: "Steve Rogers",
first_appearance: "Captain America Comics #1",
characters: "Steve Rogers"
},
{
superhero: "Iron Man",
publisher: "Marvel Comics",
alter_ego: "Tony Stark",
first_appearance: "Tales of Suspense #39",
characters: "Tony Stark"
},
{
superhero: "Thor",
publisher: "Marvel Comics",
alter_ego: "Thor Odinson",
first_appearance: "Journey into Myster #83",
characters: "Thor Odinson"
},
{
superhero: "Hulk",
publisher: "Marvel Comics",
alter_ego: "Bruce Banner",
first_appearance: "The Incredible Hulk #1",
characters: "Bruce Banner"
},
{
superhero: "Wolverine",
publisher: "Marvel Comics",
alter_ego: "James Howlett",
first_appearance: "The Incredible Hulk #180",
characters: "James Howlett"
},
{
superhero: "Daredevil",
publisher: "Marvel Comics",
alter_ego: "Matthew Michael Murdock",
first_appearance: "Daredevil #1",
characters: "Matthew Michael Murdock"
},
{
superhero: "Hawkeye",
publisher: "Marvel Comics",
alter_ego: "Clinton Francis Barton",
first_appearance: "Tales of Suspense #57",
characters: "Clinton Francis Barton"
},
{
superhero: "Cyclops",
publisher: "Marvel Comics",
alter_ego: "Scott Summers",
first_appearance: "X-Men #1",
characters: "Scott Summers"
},
{
superhero: "Silver Surfer",
publisher: "Marvel Comics",
alter_ego: "Norrin Radd",
first_appearance: "The Fantastic Four #48",
characters: "Norrin Radd"
}
];
// using the methods on the Array.prototype
// when using the built in array methods we can chain them all together.
// The result of the previous method becomes the input array of the next in the chain. Chaining methods
// is a subject for another day.
superheroNamesOfMarvel = heroes
.map(hero => {
return { name: hero.superhero, publisher: hero.publisher };
})
.filter(hero => {
return hero.publisher == "Marvel Comics";
})
.reduce((acc, curr) => {
acc.push(curr.name);
return acc;
}, []);
// using the function implementations
// Using map to include a reduced set of properties on each object.
let superheroNamesOfDC = map(heroes, hero => {
return { name: hero.superhero, publisher: hero.publisher };
});
// Using filter to only include heroes from DC
superheroNamesOfDC = filter(superheroNamesOfDC, hero => {
return hero.publisher == "DC Comics";
});
// using reduce to reduce the data set to a simple list of strings consisting of the names
superheroNamesOfDC = reduce(
superheroNamesOfDC,
(acc, curr) => {
acc.push(curr.name);
return acc;
},
[]
);
console.log(superheroNamesOfDC);
console.log(superheroNamesOfMarvel);
function map(array, cb) {
let i;
let total = [];
for (i = 0; i < array.length; i += 1) {
total.push(cb(array[i]));
}
return total;
}
// test out the map function
const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
const doubled = map(arr, item => {
return item * 2;
});
console.log(doubled);
// implement filter function
function filter(array, cb) {
let i;
let filtered = [];
for (i = 0; i < array.length; i += 1) {
if (cb(array[i])) {
filtered.push(array[i]);
}
}
return filtered;
}
// test out the filter function
const arr2 = [
{ name: "Bently", age: 2 },
{ name: "Zaphy", age: 12 },
{ name: "Domino", age: 11 }
];
const ageGreaterThanFive = filter(arr2, r => {
return r.age > 5;
});
console.log(ageGreaterThanFive);
/* output
2, 4, 6, 8, 10, 12, 14, 16, 18, 20 ]
[ { name: 'Zaphy', age: 12 }, { name: 'Domino', age: 11 } ]
*/
// implement reduce function
function reduce(array, cb, accumulator) {
let i;
for (i = 0; i < array.length; i += 1) {
if (!accumulator) {
accumulator = array[i];
}
accumulator = cb(accumulator, array[i]);
}
return accumulator;
}
const arr3 = [1, 2, 3, 4];
const arr4 = [
{ key1: "test1", key2: "test2" },
{ key1: "test3", key2: "test4" },
{ key1: "test5", key2: "test6" },
{ key1: "test7", key2: "test8" },
{ key1: "test9", key2: "test10" },
{ key1: "test11", key2: "test12" },
{ key1: "test13", key2: "test14" },
{ key1: "test15", key2: "test16" }
];
// test out the method on simple numbers and objects.
const summed = reduce(arr3, num => {
return 2 * num;
});
console.log(summed);
combinedObjects = reduce(
arr4,
(acc, obj) => {
acc.push(obj.key1);
return acc;
},
[]
);
console.log(combinedObjects);
/* output
[ 'test1',
'test3',
'test5',
'test7',
'test9',
'test11',
'test13',
'test15' ]
*/
function multiplyBy2(arr, num) {
const newArr = [];
for (let i = 0; i < arr.length; i += 1) {
newArr.push(arr[i] * num);
}
return newArr;
}
console.log(multiplyBy2([1, 2, 3, 4, 5, 6], 2));
const heroes = [
{
superhero: "Batman",
publisher: "DC Comics",
alter_ego: "Bruce Wayne",
first_appearance: "Detective Comics #27",
characters: "Bruce Wayne"
},
{
superhero: "Superman",
publisher: "DC Comics",
alter_ego: "Kal-El",
first_appearance: "Action Comics #1",
characters: "Kal-El"
},
{
superhero: "Flash",
publisher: "DC Comics",
alter_ego: "Jay Garrick",
first_appearance: "Flash Comics #1",
characters: "Jay Garrick, Barry Allen, Wally West, Bart Allen"
},
{
superhero: "Green Lantern",
publisher: "DC Comics",
alter_ego: "Alan Scott",
first_appearance: "All-American Comics #16",
characters:
"Alan Scott, Hal Jordan, Guy Gardner, John Stewart, Kyle Raynor, Jade, Sinestro, Simon Baz"
},
{
superhero: "Green Arrow",
publisher: "DC Comics",
alter_ego: "Oliver Queen",
first_appearance: "More Fun Comics #73",
characters: "Oliver Queen"
},
{
superhero: "Wonder Woman",
publisher: "DC Comics",
alter_ego: "Princess Diana",
first_appearance: "All Star Comics #8",
characters: "Princess Diana"
},
{
superhero: "Martian Manhunter",
publisher: "DC Comics",
alter_ego: "J'onn J'onzz",
first_appearance: "Detective Comics #225",
characters: "Martian Manhunter"
},
{
superhero: "Robin/Nightwing",
publisher: "DC Comics",
alter_ego: "Dick Grayson",
first_appearance: "Detective Comics #38",
characters: "Dick Grayson"
},
{
superhero: "Blue Beetle",
publisher: "DC Comics",
alter_ego: "Dan Garret",
first_appearance: "Mystery Men Comics #1",
characters: "Dan Garret, Ted Kord, Jaime Reyes"
},
{
superhero: "Black Canary",
publisher: "DC Comics",
alter_ego: "Dinah Drake",
first_appearance: "Flash Comics #86",
characters: "Dinah Drake, Dinah Lance"
},
{
superhero: "Spider Man",
publisher: "Marvel Comics",
alter_ego: "Peter Parker",
first_appearance: "Amazing Fantasy #15",
characters: "Peter Parker"
},
{
superhero: "Captain America",
publisher: "Marvel Comics",
alter_ego: "Steve Rogers",
first_appearance: "Captain America Comics #1",
characters: "Steve Rogers"
},
{
superhero: "Iron Man",
publisher: "Marvel Comics",
alter_ego: "Tony Stark",
first_appearance: "Tales of Suspense #39",
characters: "Tony Stark"
},
{
superhero: "Thor",
publisher: "Marvel Comics",
alter_ego: "Thor Odinson",
first_appearance: "Journey into Myster #83",
characters: "Thor Odinson"
},
{
superhero: "Hulk",
publisher: "Marvel Comics",
alter_ego: "Bruce Banner",
first_appearance: "The Incredible Hulk #1",
characters: "Bruce Banner"
},
{
superhero: "Wolverine",
publisher: "Marvel Comics",
alter_ego: "James Howlett",
first_appearance: "The Incredible Hulk #180",
characters: "James Howlett"
},
{
superhero: "Daredevil",
publisher: "Marvel Comics",
alter_ego: "Matthew Michael Murdock",
first_appearance: "Daredevil #1",
characters: "Matthew Michael Murdock"
},
{
superhero: "Hawkeye",
publisher: "Marvel Comics",
alter_ego: "Clinton Francis Barton",
first_appearance: "Tales of Suspense #57",
characters: "Clinton Francis Barton"
},
{
superhero: "Cyclops",
publisher: "Marvel Comics",
alter_ego: "Scott Summers",
first_appearance: "X-Men #1",
characters: "Scott Summers"
},
{
superhero: "Silver Surfer",
publisher: "Marvel Comics",
alter_ego: "Norrin Radd",
first_appearance: "The Fantastic Four #48",
characters: "Norrin Radd"
}
];
// using the methods on the Array.prototype
// when using the built in array methods we can chain them all together.
// The result of the previous method becomes the input array of the next in the chain. Chaining methods
// is a subject for another day.
superheroNamesOfMarvel = heroes
.map(hero => {
return { name: hero.superhero, publisher: hero.publisher };
})
.filter(hero => {
return hero.publisher == "Marvel Comics";
})
.reduce((acc, curr) => {
acc.push(curr.name);
return acc;
}, []);
// using the function implementations
// Using map to include a reduced set of properties on each object.
let superheroNamesOfDC = map(heroes, hero => {
return { name: hero.superhero, publisher: hero.publisher };
});
// Using filter to only include heroes from DC
superheroNamesOfDC = filter(superheroNamesOfDC, hero => {
return hero.publisher == "DC Comics";
});
// using reduce to reduce the data set to a simple list of strings consisting of the names
superheroNamesOfDC = reduce(
superheroNamesOfDC,
(acc, curr) => {
acc.push(curr.name);
return acc;
},
[]
);
console.log(superheroNamesOfDC);
console.log(superheroNamesOfMarvel);
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