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All about arrays

Arrays are lists lists of of data.

Array.prototype.forEach()

The forEach array method takes a callback function as a parameter, and will run the callback on each item of the array.

Array.prototype.map()

The map array method takes callback function which runs on each item in the array, and will create a new array.

Array.prototype.reduce()

The reduce array method takes callback function which runs on each item in the array, and will a single value.

The callback function takes two parameters (previousValue, currentValue). In addition to a callback function, the reduce method also takes a parameter for initial value. reduce(callbackFunction, startValue)

Challenge 1

Solution 1

Challenge 2

Solution 2

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/**
* Challenge 1
* Use the 'reduce' method to calculate total from cartItems
*/
​
const cartItems = [
  { name: 'Shoes', price: 67 },
  { name: 'Hat', price: 24 },
  { name: 'Socks', price: 15 },
]
​
// const total = cartItems.reduce(???)
​
console.log(total)

press 'run' to view console output