Making Wordpress user metadata available to Rest-API - wordpress

Question

I am building an Ionic app that ties into my Wordpress website Rest API. While I have figured out how to populate post and page data, I am having a very difficult time populating user data.
Specifically, I am trying to access user data stored as usermeta by a third party plugin called UPME (User Profiles Made Easy). It is stored as user metadata in the database.
Here is an image of what I envision pulling from the API into the app.
For example, user_id: 43 meta_key: linkedin within the database.
Can someone please give me an example of what I can do in my functions.php to be able to populate every user with {...} meta_keys into the API for outside things to access?
EDIT: This is my understanding of what it should do
I need some function within Wordpress that makes the following available to my Rest-API:
• Get list of all users
• For all users {
• If user upme_user_profile_status: ACTIVE
• Get the following usermeta: [
first_name
last_name
company_name
company_title
user_email
business_phone
facebook
twitter
linkedin
]
}
This would be publicly accessible within the API.

Answer 1

I think this should help you. As well as WP user query for reference.
Example to display all subscribers in an unordered list.
<?php
$blogusers = get_users( 'blog_id=1&orderby=nicename&role=subscriber' );
// Array of WP_User objects.
foreach ( $blogusers as $user ) {
echo '<span>' . esc_html( $user->user_email ) . '</span>';
}
Example of querying by a specific field.
<?php
$blogusers = get_users( array( 'fields' => array( 'display_name' ) ) );
// Array of stdClass objects.
foreach ( $blogusers as $user ) {
echo '<span>' . esc_html( $user->display_name ) . '</span>';
}