import { RichTextFormat } from './types';

/**
 * Optimised equality check for format objects.
 *
 * @param {?RichTextFormat} format1 Format to compare.
 * @param {?RichTextFormat} format2 Format to compare.
 *
 * @return {boolean} True if formats are equal, false if not.
 */
export function isFormatEqual( format1: RichTextFormat, format2: RichTextFormat ): boolean {
	// Both not defined.
	if ( format1 === format2 ) {
		return true;
	}

	// Either not defined.
	if ( ! format1 || ! format2 ) {
		return false;
	}

	if ( format1.type !== format2.type ) {
		return false;
	}

	const attributes1 = format1.attributes;
	const attributes2 = format2.attributes;

	// Both not defined.
	if ( attributes1 === attributes2 ) {
		return true;
	}

	// Either not defined.
	if ( ! attributes1 || ! attributes2 ) {
		return false;
	}

	const keys1 = Object.keys( attributes1 );
	const keys2 = Object.keys( attributes2 );

	if ( keys1.length !== keys2.length ) {
		return false;
	}

	const length = keys1.length;

	// Optimise for speed.
	for ( let i = 0; i < length; i++ ) {
		const name = keys1[ i ];

		if ( attributes1[ name ] !== attributes2[ name ] ) {
			return false;
		}
	}

	return true;
}