Using a javascript file to access a get posts array

Yep, you’re looking for wp_localize_script(). Do away with the global.

add_action( 'wp_enqueue_scripts', 'wpse_enqueue_scripts' );
function wpse_enqueue_scripts() {
    wp_enqueue_script( 'wpse-main', get_template_directory_uri() . '/path/to/script.js', array(), false, true );
    wp_localize_script( 'wpse-main', 'wpseVars', array(
        'postsLoop1' => json_encode( /* first post array */ ),
        'postsLoop2' => json_encode( /* second post array */ ),
        'postsLoop3' => json_encode( /* third post array */ )
    ) );
}

Then in your script, you can access the variables by grabbing wpseVars.postsLoop1, wpseVars.postsLoop2, etc.