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JavaScript JavaScript Array Iteration Methods Combining Array Methods Array Flattening

Liam Hayes
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Liam Hayes
Full Stack JavaScript Techdegree Student 13,116 Points
Posted by Liam Hayes
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Liam Hayes
Full Stack JavaScript Techdegree Student 13,116 Points

Array Flattening Code Challenge

Not sure whatsoever how to solve this, would love some help or hints. Thank you very much :)

Challenge Task 1 of 1
Using reduce method, flatten the customerNames array of arrays. In other words, take all the names from each array inside customerNames and place them in one big array. Store the flattened array in the flattenedCustomerNames variable. You can use the array in the comments below for reference.
app.js 
const customerNames = [
    [ "John", "Sandy", "Tyrone", "Elizabeth", "Penny" ],
    [ "Barry", "Wanda", "Jamal", "Hayden" ],
    [ "Portia", "Pam", "Philip" ]
];
let flattenedCustomerNames;

// flattenedCustomerNames should be: ["John", "Sandy", "Tyrone", "Elizabeth", "Penny", "Barry", "Wanda", "Jamal", "Hayden", "Portia", "Pam", "Philip"]
// Write your code below

2 Answers

Evaldas Burlingis
Evaldas Burlingis
7,020 Points
Evaldas Burlingis
Evaldas Burlingis
7,020 Points

One of the simplier ways to solve this would be make empty array of flattenedCustomerNames and then with for loop to fill it with customerNames array.

ANSWER BELOW 

const customerNames = [
    [ "John", "Sandy", "Tyrone", "Elizabeth", "Penny" ],
    [ "Barry", "Wanda", "Jamal", "Hayden" ],
    [ "Portia", "Pam", "Philip" ]
];

let flattenedCustomerNames;

// flattenedCustomerNames should be: ["John", "Sandy", "Tyrone", "Elizabeth", "Penny", "Barry", "Wanda", "Jamal", "Hayden", "Portia", "Pam", "Philip"]
// Write your code below

flattenedCustomerNames = [];

for(let i = 0; i < customerNames.length; i++){
  flattenedCustomerNames =  flattenedCustomerNames.concat(customerNames[i]);
}
console.log(flattenedCustomerNames);

ANSWER TO PASS YOUR CHALLENGE 

flattenedCustomerNames = customerNames.reduce((acc, cu) => acc.concat(cu), []);

Very well written article about reduce and when to use it: https://medium.freecodecamp.org/reduce-f47a7da511a9

To read more about reduce method : https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce

Muhammad Anwar Ul Haq
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Muhammad Anwar Ul Haq
Full Stack JavaScript Techdegree Graduate 18,781 Points
Muhammad Anwar Ul Haq
.a{fill-rule:evenodd;}techdegree seal-36
Muhammad Anwar Ul Haq
Full Stack JavaScript Techdegree Graduate 18,781 Points 
flattenedCustomerNames = customerNames.reduce ((innerNames, names ) => innerNames.concat(names), [] );