Conditionally Enqueue JS file to certain pages of WP site. Specifically, NOT enqueue certain pages on WP site

functions.php

<?php

//Function to add custom.js functionality to header only if the page is NOT contact page
add_action( 'wp_enqueue_scripts', 'conditional_header');
function conditional_header(){
	if(is_page('contact') == false){
		wp_enqueue_script(
			'custom',
			get_stylesheet_directory_uri() . '/js/custom.js',
			array('jquery'),
			null,
			true
		);
	}	
}