Fix ESLint warnings (and one actual bug)

basic.js

@@ -1233,7 +1233,7 @@ this.basic = (function() {
       (function(source) {
         function munge(kw) {
           // Escape special characters
-          function escape(c) { return (/[\[\]\\\^\$\.\|\?\*\+\(\)]/).test(c) ? '\\' + c : c; }
+          function escape(c) { return (/[[\]\\^$.|?*+()]/).test(c) ? '\\' + c : c; }
           // Allow linear whitespace between characters
           //return kw.split('').map(escape).join('[ \\t]*');
 
@@ -1268,9 +1268,9 @@ this.basic = (function() {
         var regexReservedWords = new RegExp("^(" + RESERVED_WORDS.map(munge).join("|") + ")", "i"),
             regexIdentifier = /^([A-Za-z][A-Za-z0-9]?)[A-Za-z0-9]*(\$|%)?/,
             regexStringLiteral = /^"([^"]*?)(?:"|(?=\n|\r|$))/,
-            regexNumberLiteral = /^[0-9]*\.?[0-9]+(?:[eE]\s*[\-+]?\s*[0-9]+)?/,
+            regexNumberLiteral = /^[0-9]*\.?[0-9]+(?:[eE]\s*[-+]?\s*[0-9]+)?/,
             regexHexLiteral = /^\$[0-9A-Fa-f]+/,
-            regexOperator = /^[;=<>+\-*\/\^(),]/,
+            regexOperator = /^[;=<>+\-*/^(),]/,
 
             regexLineNumber = /^[0-9]+/,
             regexSeparator = /^:/,

dos.js

@@ -151,18 +151,13 @@ function DOS(tty) {
     if (file === null) {
       // Not cached - do a synchronous XmlHttpRequest for the file here
       req = new XMLHttpRequest();
-      try {
-        url = "vfs/" + encodeURIComponent(filename.replace(/\./g, '_')) + ".txt";
-        async = false;
-        req.open("GET", url, async);
-        req.send(null);
-        if (req.status === 200 || req.status === 0) { // 0 for file:// protocol
-          file = req.responseText.replace(/\r\n/g, "\r");
-          vfs_set(filename, file);
-        }
-      } catch (e) {
-        // File doesn't exist - APPEND/READ will fail
-        throw e;
+      url = "vfs/" + encodeURIComponent(filename.replace(/\./g, '_')) + ".txt";
+      async = false;
+      req.open("GET", url, async);
+      req.send(null);
+      if (req.status === 200 || req.status === 0) { // 0 for file:// protocol
+        file = req.responseText.replace(/\r\n/g, "\r");
+        vfs_set(filename, file);
       }
     }
 
@@ -179,7 +174,7 @@ function DOS(tty) {
     // Normal open logic
     open(filename, recordlength);
 
-    if (!buffers.hasOwnProperty(filename)) {
+    if (!Object.prototype.hasOwnProperty.call(buffers, filename)) {
       doserror(DOSErrors.FILE_NOT_FOUND);
     }
 
@@ -196,7 +191,7 @@ function DOS(tty) {
     // If not specified, close all buffers
     if (!filename) {
       for (fn in buffers) {
-        if (buffers.hasOwnProperty(fn)) {
+        if (Object.prototype.hasOwnProperty.call(buffers, fn)) {
           close(fn);
         }
       }

hires.js

@@ -87,7 +87,10 @@ function HiRes(element, width, height) {
         err = dx - dy,
         e2;
 
-    while (true) {
+    last_x = x;
+    last_y = y;
+
+    for (;;) {
       this.plot(x0, y0);
 
       if (x0 === x1 && y0 === y1) { return; }
@@ -101,9 +104,6 @@ function HiRes(element, width, height) {
         y0 += sy;
       }
     }
-    last_x = x;
-    last_y = y;
-
   };
 
   this.getPixel = function(x, y) {