function validate( node ) {
		var flags;
		var found;
		var jsdoc;
		var desc;
		var word;
		var idx;
		var ast;
		var i;

		jsdoc = findJSDoc( source, node );
		if ( isObject( jsdoc ) ) {
			ast = parseJSDoc( jsdoc.value, DOPTS );
			desc = ast.description;
			idx = desc.search( reEOL.REGEXP );
			if ( idx !== -1 ) {
				// Only first line contains the description:
				desc = desc.substr( 0, idx );
			}
			// Do not raise an error for JSDoc comments without descriptions:
			if ( desc.length ) {
				flags = {};
				if ( !endsWith( desc, '.' ) ) {
					flags.missingPeriod = true;
				}
				if ( !isCapitalized( desc ) && !desc.match( RE_NUM ) ) {
					// Check whether description starts with a word from the whitelist:
					found = false;
					for ( i = 0; i < opts.whitelist.length; i++ ) {
						word = opts.whitelist[ i ];
						if ( startsWith( desc, word+' ' ) ) {
							found = true;
							break;
						}
					}
					// If not, raise an error:
					if ( !found ) {
						flags.missingCapital = true;
					}
				}
				if ( flags.missingPeriod || flags.missingCapital ) {
					return report( jsdoc, desc, flags );
				}
			}
		}
	}
Checks whether JSDoc comments have a capitalized description that ends with a period.

@private
@param {ASTNode} node - AST node
@returns {void}