Elegant way to select key in object of an array

Question

Consider having the following json

[
{'key1': { ... }},
{'key2': { ... }},
{'key3': { ... }}
]

I want to extract the keys for those objects in an elegant way, the following code is working, but it seems ugly to me.

let result = objects.map(o => Object.keys(o))[0]

the [0] at the end because the returned value is an array of array

Answer 1

You can use .concat() and .map() methods to get the desired result:

let data = [
  {'key1': { }},
  {'key2': { }},
  {'key3': { }}
];

let result = [].concat(...data.map(Object.keys));

console.log(result);

References:

• Array.prototype.concat()
• Array.prototype.map()
• Object.keys()
• Spread Syntax