JAVASCRIPT

use .map(), .filter() js

var arr = [1, 25, 20, 4];

var sum = arr.map((item) => item * 10).filter((item) => item > 100);
var sum2 = arr.map((item) => item * 10)
console.log("sum2", sum2)
// sum2 : (4) [10, 250, 200, 40]
console.log("sum", sum);
// sum : (2) [250, 200]

Map and Filter methods used together

const list = ['Apple', 'Orange', 'Egg']
list.map(item => item[0]).filter(item => item === 'A') //'A'

javavscript array.filter with array.map

var arr = [1, 25, 20, 4];

var sum = arr.map((item) => item * 10).filter((item) => item > 100);
var sum2 = arr.map((item) => item * 10)
console.log("sum2", sum2)
// sum2 : (4) [10, 250, 200, 40]
console.log("sum", sum);
// sum : (2) [250, 200]

map and filter js

var options = [
  { name: 'One', assigned: true }, 
  { name: 'Two', assigned: false }, 
  { name: 'Three', assigned: true }, 
];

var reduced = options.reduce(function(filtered, option) {
  if (option.assigned) {
     var someNewValue = { name: option.name, newProperty: 'Foo' }
     filtered.push(someNewValue);
  }
  return filtered;
}, []);

document.getElementById('output').innerHTML = JSON.stringify(reduced);
<h1>Only assigned options</h1>
<pre id="output"> </pre>

map & filter

const filteredList = watchList.map(movie => ({
  title : movie['Title'],
  rating: movie["imdbRating"]
})
).filter(movie => {
  return parseFloat(movie.rating) >= 8.0;
})

map&filter

const files = [ 'foo.txt ', '.bar', '   ', 'baz.foo' ];
const filePaths = files
  .map(file => file.trim())
  .filter(Boolean)
  .map(fileName => `~/cool_app/${fileName}`);

// filePaths = [ '~/cool_app/foo.txt', '~/cool_app/.bar', '~/cool_app/baz.foo']

map&filter

const files = [ 'foo.txt ', '.bar', '   ', 'baz.foo' ];
const filePaths = files.reduce((acc, file) => {
  const fileName = file.trim();
  if(fileName) {
    const filePath = `~/cool_app/${fileName}`;
    acc.push(filePath);
  }
  return acc;
}, []);

// filePaths = [ '~/cool_app/foo.txt', '~/cool_app/.bar', '~/cool_app/baz.foo']

Filter and map an array3

// Only change code below this line
const filteredList = watchList
  .filter(({ imdbRating }) => imdbRating >= 8.0)
  .map(({ Title: title, imdbRating: rating }) => ({ title, rating }));
// Only change code above this line

console.log(filteredList);

Filter and map an array

const filteredList = watchList
  .filter(movie => {
    // return true it will keep the item
    // return false it will reject the item
    return parseFloat(movie.imdbRating) >= 8.0;
  })
  .map(movie => {
    return {
      title: movie.Title,
      rating: movie.imdbRating
    };
  });