Working with the WordPress REST API can be both fun and annoying. Having data and code separated just feels right. However, there are some catches. Adding basic things like meta-tags for example is not as straight forward as I thought. But let`s do it anyway, it`s fun they said!
The “Problem”
Working with the NEXT.JS WordPress example you get the following response from post.tags.edges:

So, we have an array with objects, Wohoo! The problem is that we can`t loop straight trough them. since “return” tells React to return your component.
The Sollution
The solution is simple. Create an empty array like this:
const tagItems = []
Then loop trough post.tags.edges and push them to your empty array.
tagArray = post.tags.edges; let i; for(i = 0; i < tagArray.length; i++ ) { tagItems.push(tagArray[i].node.name) }
The Meta tag
Next, you have to import Head from next/head like this:
import Head from 'next/head'
Then add your meta inside of <Head> like this:
<Head> <title> {post.title} </title> <meta name="keywords" content={tagItems} /> </Head>
And we`re done! There are other and maybe better ways of doing this.
See more here: https://flaviocopes.com/react-how-to-loop/