wp-api-select2.js

this.$el.find( '.taxonomy-terms' ).select2({
	multiple: true,
	ajax: {
		url: WP_API_Settings.root + 'wp/v2/terms/' + this.options.taxonomy.slug,
		data: function( term, page ) {
			return {
				search: term,
				page: page,
				_envelope: true
			}
		},
		results: function( data, page ) {
			return {
				results: data.body.map( function( term ) {
					return { text: term.name, id: term.id };
				} ),
				more: data.headers['X-WP-TotalPages'] > page
			}
		}
	},
	width: '100%'
});