Merge pull request #241 from BrainJS/217-unrecognized-handler

Provide fix for #217 unrecognized handler

Author: robertleeplummerjr

browser.js

@@ -1,7 +1,7 @@
 {
   "name": "brain.js",
   "description": "Neural network library",
-  "version": "1.2.2",
+  "version": "1.2.3",
   "author": "Heather Arthur <[email protected]>",
   "repository": {
     "type": "git",

browser.min.js

@@ -766,6 +766,7 @@ RNN.defaults = {
           values.push(data[i].output);
         }
         this.dataFormatter = DataFormatter.fromArrayInputOutput(values);
+        this.dataFormatter.addUnrecognized();
       }
       for (let i = 0, max = data.length; i < max; i++) {
         result.push(this.formatDataIn(data[i].input, data[i].output));

dist/recurrent/rnn.js

@@ -60,7 +60,11 @@ export default class DataFormatter {
       let character = value[i];
       let index = indexTable[character];
       if (index === undefined) {
-        throw new Error(`unrecognized character "${ character }"`);
+        if (indexTable['unrecognized']) {
+          index = indexTable['unrecognized'];
+        } else {
+          throw new Error(`unrecognized character "${ character }"`);
+        }
       }
       if (index < maxThreshold) continue;
       result.push(index);
@@ -87,15 +91,20 @@ export default class DataFormatter {
   }
 
   toCharacters(indices, maxThreshold = 0) {
-    let result = [];
-    let characterTable = this.characterTable;
+    const result = [];
+    const characterTable = this.characterTable;
+    const indexTable = this.indexTable;
 
     for (let i = 0, max = indices.length; i < max; i++) {
       let index = indices[i];
       if (index < maxThreshold) continue;
       let character = characterTable[index];
       if (character === undefined) {
-        throw new Error(`unrecognized index "${ index }"`);
+        if (indexTable['unrecognized']) {
+          character = characterTable[indexTable['unrecognized']];
+        } else {
+          throw new Error(`unrecognized index "${ index }"`);
+        }
       }
       result.push(character);
     }
@@ -112,6 +121,10 @@ export default class DataFormatter {
     this.addSpecial('start-output');
   }
 
+  addUnrecognized() {
+    this.addSpecial('unrecognized');
+  }
+
   static fromAllPrintable(maxThreshold, values = ['\n']) {
     for(let i = 32; i <= 126; i++) {
       values.push(String.fromCharCode(i));

dist/recurrent/rnn.js.map

@@ -35,6 +35,17 @@ describe('rnn', () => {
       net.runBackpropagate([1, 1, 0]);
       assert(net.model.input.deltas.some(notZero));
     });
+    it('can handle unrecognized input characters', () => {
+      var net = new RNN({ hiddenSizes: [3] });
+      net.train([
+        { input: '1', output: '2' },
+        { input: '2', output: '3' },
+      ]);
+
+      assert.doesNotThrow(() => {
+        net.run('7');
+      });
+    });
   });
   describe('xor', () => {
     function xorNet() {