Available on: InDom

Returns true if the underlying element has a data-* attribute or in its internal memory map, otherwise false.
Available only for objects whose underlying element is connected to the DOM, ensuring internal state consistency.

Parameters:

Returns: {boolean} - true when the key exists, false otherwise

Throws:

Examples:

const div = $1('.example>div');

// click-counter stored in memory
div.onClick(() => {
	// read counter (default 0 if never stored)
	const clicks = div.getData('clicked') ?? 0;
	div.setData('clicked', clicks + 1);
});

// store object and int
div.setData('user', { id: 34, name: 'Bob' });
console.log(div.hasData('user') ? 'has data key: user'
	: 'doesn\'t have data key: user');
//has data key: user

div.setData('test', 1);

console.log([div.getData('user'), div.getData('test')]); // [{id: 34, name: 'Bob'}, 1]

// remove only 'user'
div.removeData('user');
console.log([div.getData('user'), div.getData('test')]); // [undefined, 1]	


// grab every editable field inside the first .input-examples
const fields = $a('input, textarea, select', $1('.input-examples'));

// snapshot original values as JSON strings
fields.each(n => n.setData('originalValue', JSON.stringify(n.getValue())));

// button to check if anything changed
$1('body').append('
Any field modified?
');
$1('.checkBtn').onClick(() => {
	// InDomArray extends Array and inherits all standard array methods.
	// true if any field's current value differs from its snapshot (stops at first true)
	const modified = fields.some(n =>
		n.getData('originalValue') !== JSON.stringify(n.getValue())
	);
	console.log(modified ? 'modified' : 'same');
});

{
	// The above is to demonstrate different concepts because with InDom you could just:
	const section = $1('.input-examples');
	$1('body').append('
Any field modified? (rw)
');
	const original = JSON.stringify($v(section));
	$1('.rwCheckBtn').onClick(() => console.log(
		original === JSON.stringify($v(section)) ? 'same' : 'modified'
	));
}