nl_tokens: An extension of the same - value algorithm as [ described for use by ES6 Map and Set ] ( https : // developer . mozilla . org / en - US / docs / Web / JavaScript / Reference / Global_Objects / Map#Key_equality )
pl_tokens: function is ( valueA , valueB ) { if ( valueA === valueB || ( valueA !== valueA && valueB !== valueB ) ) { return <mask> ; } if ( ! valueA || ! valueB ) { return false ; } if ( typeof valueA . valueOf === 'function' && typeof valueB . valueOf === 'function' ) { valueA = valueA . valueOf ( ) ; valueB = valueB . valueOf ( ) ; if ( valueA === valueB || ( valueA !== valueA && valueB !== valueB ) ) { return true ; } if ( ! valueA || ! valueB ) { return false ; } } if ( typeof valueA . equals === 'function' && typeof valueB . equals === 'function' && valueA . equals ( valueB ) ) { return true ; } return false ; }