feat: initial checkin

Current state of affairs will retrieve a framebuffer, if one exists. Not
yet a promised version as i experience ongoing probs with my limited
brain capacity.

index.js

@@ -0,0 +1,53 @@
+// Find our matrix in all available framebuffers
+
+"use strict";
+
+const fsp = require('fs-promise'),
+  glob = require('glob-promise'),
+  path = require('path'),
+  Stream = require('streamjs'),
+
+  // the framebuffer's name file
+  namefile = framebuffer => path.join(framebuffer, 'name'),
+
+  // Linux file spec for framebuffers
+  prospects = glob('/sys/class/graphics/fb*'),
+
+  // predicte: has a name file
+  // Promise hasNamefile = dir => fsp.statSync(namefile(dir)).then(stat => stat.isFile()),
+  // exists() is deprecated in favour of stat(), but stat throws an Error, which i cannot
+  // handle taking my limited Javascript into consideration
+  // hasNamefile = dir => fsp.statSync(namefile(dir)),
+  hasNamefile = dir => fsp.existsSync(namefile(dir)),
+
+  // Predicate: framebuffer is a Sense HAT LED matrix
+  isSenseHatMatrix = dir => {
+    // Promise return fsp.readFileSync(namefile(dir)).then(buf => 'RPi-Sense FB\n' === b.toString());
+    const s = fsp.readFileSync(namefile(dir)).toString().trim();
+    // Ignore any trailing EOL
+    const p = 'RPi-Sense FB' === s;
+    return p;
+  },
+
+  // Returns an Optional, which is also called a Maybe in other languages
+  fb = prospects.then(a => {
+    let r = Stream(a)
+      .filter(hasNamefile)
+      .filter(isSenseHatMatrix)
+      .findFirst();
+    return r;
+  }),
+
+  rc = fb.then(a => {
+    if (a.isPresent()) {
+      const led = a.get();
+      console.log(`Found framebuffer ${led}`);
+      return led;
+    } else {
+      console.log('Cannot find a Raspberry Pi Sense HAT matrix LED!' +
+	      'Are we running on a Pi?');
+      return null;
+    }
+  });
+
+// EOF