nl_tokens: Save a wallet to a file .
pl_tokens: function saveWallet ( filename , walletData ) { return new Promise ( ( resolve , reject ) => { fs . writeFile ( filename , JSON . stringify ( walletData , null , 2 ) , function ( err ) { if ( <mask> ) return reject ( console . error ( err ) ) //console.log(`${name}.json written successfully.`) return resolve ( ) } ) } ) }