Iterators

Functions Assigned to Variables

let plusFive = (number) => {
  return number + 5;
};
// f is assigned the value of plusFive
let f = plusFive;

plusFive(3); // 8
// Since f has a function value, it can be invoked.
f(9); // 14

Callback Functions

const isEven = (n) => {
  return n % 2 == 0;
};

let printMsg = (evenFunc, num) => {
  const isNumEven = evenFunc(num);
  console.log(`${num} is an even number: ${isNumEven}.`);
};

// Pass in isEven as the callback function
printMsg(isEven, 4);
// => The number 4 is an even number: True.

Array.reduce()

const numbers = [1, 2, 3, 4];

const sum = numbers.reduce((accumulator, curVal) => {
  return accumulator + curVal;
});

console.log(sum); // 10

Array.map()

const members = ["Taylor", "Donald", "Don", "Natasha", "Bobby"];

const announcements = members.map((member) => {
  return member + " joined the contest.";
});

console.log(announcements);

Array.forEach()

const numbers = [28, 77, 45, 99, 27];

numbers.forEach((number) => {
  console.log(number);
});

Array.filter()

const randomNumbers = [4, 11, 42, 14, 39];
const filteredArray = randomNumbers.filter((n) => {
  return n > 5;
});

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