JavaScript that edits a term meta value in a WordPress custom taxonomy

edit-term-meta.js

//edit a term meta value in our Transmission custom taxonomy
let terms = new wp.api.collections.Tranmission();
terms.fetch().done( function( t ){
	let target = t.find( x => 'automatic' === x.slug );
	if( ! target ) { return; }
	jQuery.ajax({
		method: 'POST',
		url: myplugin.rest_base_url + 'wp/v2/transmission/' + target.id,
		//save the number 6 in a term meta key 'speeds'
		data: { meta: { 'speeds': 6 } },
		beforeSend: function ( xhr ) {
			xhr.setRequestHeader( 'X-WP-Nonce', myplugin.nonce ); //must be wp_create_nonce( 'wp_rest' ), see paragraph 4 https://developer.wordpress.org/rest-api/using-the-rest-api/authentication/
		},
	});
});