CODEWITHSUNDEEP
javascriptarraysecmascript-6
Patricio Vargas
Patricio Vargas

Reputation: 5522

Returning properties of array of array of values Javascript

I need to know if there's a fancy way to return an array of strings created by the properties of an array of objects. The property of those objects it's also an array.

E.g Data:

[
 {
  servicesOffered: ["x","Y"]
 },
 {
  servicesOffered: ["z","w"]
 }
]

I tried to be fancy using the spread operator but doesn't work. I know I can iterate again the array of servicesOffered, but I don't know if there's a fancier or better way to do this.

Code:

 getServices(results: Business[]): string[] {
    return results.map(({ servicesOffered }) => {
      const t = servicesOffered;
      return ...t;
    });
  }

Expected Output

["x","Y","z","w"]

Upvotes: 0

Views: 47

Answers (2)

Ele
Ele

Reputation: 33726

Using the function reduce.

let arr = [ {  servicesOffered: ["x","Y"] }, {  servicesOffered:["z","w"] }],
    result = arr.reduce((a, {servicesOffered}) => a.concat(servicesOffered), []);
console.log(result);
.as-console-wrapper { max-height: 100% !important; top: 0; }

Upvotes: 1

Ori Drori
Ori Drori

Reputation: 191976

Use Array.flatMap() instead of map:

function getServices(results) {
  return results.flatMap(({ servicesOffered }) => servicesOffered);
}

const data = [{"servicesOffered":["x","Y"]},{"servicesOffered":["z","w"]}];

const result = getServices(data);

console.log(result);

If flatMap is not supported, you can use Array.map() with spread and Array.concat() to flatten the array:

function getServices(results) {
  return [].concat(...results.map(({ servicesOffered }) => servicesOffered));
}

const data = [{"servicesOffered":["x","Y"]},{"servicesOffered":["z","w"]}];

const result = getServices(data);

console.log(result);

Upvotes: 3

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