Get the first key name of a JavaScript object

user_272920 0
Viewed 283950

Let's assume we have the following JavaScript object:

ahash = {"one": [1,2,3], "two": [4,5,6]}

Is there a function that returns the first key name for the given object?

From the example above I want to get one as a result of that function.

javascript
8 Answers

You can query the content of an object, per its array position.
For instance:

 let obj = {plainKey: 'plain value'};

 let firstKey = Object.keys(obj)[0]; // "plainKey"
 let firstValue = Object.values(obj)[0]; // "plain value"

 /* or */

 let [key, value] = Object.entries(obj)[0]; // ["plainKey", "plain value"]

 console.log(key); // "plainKey"
 console.log(value); // "plain value"
user_97248020

I use Lodash for defensive coding reasons.

In particular, there are cases where I do not know if there will or will not be any properties in the object I'm trying to get the key for.

A "fully defensive" approach with Lodash would use both keys as well as get:

const firstKey = _.get(_.keys(ahash), 0);
user_8707290
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