E.connectSDCard( ) doesn't work on ESP8266

SPI1.setup({sck:14, miso:12, mosi:13});
E.connectSDCard(SPI1, 15);
console.log(require("fs").readdirSync());

result:

Uncaught Error: Function "connectSDCard" not found!
at line 1 col 3
E.connectSDCard(SPI1,15);
^
WARNING: Module "fs" not found
Uncaught Error: Field or method "readdirSync" does not already exist, and can't create it on undefined
at line 1 col 26
console.log(require("fs").readdirSync());
=undefined
FirmVer: 1v91 Copyright 2016 G.Williams