diff --git a/lib/codecs.js b/lib/codecs.js
index 3cec5c3..6e48cc3 100644
--- a/lib/codecs.js
+++ b/lib/codecs.js
@@ -1,11 +1,11 @@
-let flag_rawmode = false;
+const flag_rawmode = false;
 
 const enums = require('./enums');
 
 function arr2Hex(arr) {
     // Convert byte array to hex string
-    var hs = '';
-    for (var v in arr) { hs += toHex(arr[v],2) }
+    let hs = '';
+    for (const v in arr) { hs += toHex(arr[v],2); }
     return hs;
 }
 
@@ -16,8 +16,8 @@ function toHex(d, len) {
 
 function toByteArray(hs) {
     // Convert hex string, e.g. '21A8' to byte array: [33,168]
-    var ba = [];
-    for (var i=0; i<hs.length/2; i++) {
+    const ba = [];
+    for (let i=0; i<hs.length/2; i++) {
         ba.push(parseInt(hs.slice(2*i,2*i+2), 16));
     }
     return ba;
@@ -36,7 +36,7 @@ function uint16toVal(j, ofs=0) {
 }
 
 function sint16toVal(j, ofs=0) {
-    var v = Math.pow(2,8)*j[ofs+1]+j[ofs];
+    let v = Math.pow(2,8)*j[ofs+1]+j[ofs];
     if (v >= Math.pow(2,15)) { v -= Math.pow(2,16); }
     return v;
 }
@@ -46,7 +46,7 @@ function uint32toVal(j, ofs=0) {
 }
 
 function sint32toVal(j, ofs=0) {
-    var v = Math.pow(2,24)*j[ofs+3]+Math.pow(2,16)*j[ofs+2]+Math.pow(2,8)*j[ofs+1]+j[ofs];
+    let v = Math.pow(2,24)*j[ofs+3]+Math.pow(2,16)*j[ofs+2]+Math.pow(2,8)*j[ofs+1]+j[ofs];
     if (v >= Math.pow(2,31)) { v -= Math.pow(2,32); }
     return v;
 }
@@ -56,20 +56,17 @@ function int2val(j, ofs = 0, signed = false) {
     switch (j.length) {
         case 1 :
             return (signed ? sint08toVal(j,ofs) : uint08toVal(j,ofs) );
-            break;
         case 2 :
             return (signed ? sint16toVal(j,ofs) : uint16toVal(j,ofs) );
-            break;
         case 4 :
             return (signed ? sint32toVal(j,ofs) : uint32toVal(j,ofs) );
-            break;
         default:
             return null;
     }
 }
 
 function RawEncode(string_ascii, len) {
-    let string_bin = toByteArray(string_ascii);
+    const string_bin = toByteArray(string_ascii);
     if (string_bin.length !== len) {
         throw new Error(`String must be ${len} long`);
     }
@@ -106,21 +103,21 @@ class O3EInt {
         this.signed = signed;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         } else {
             if (this.offset != 0) {
-                throw new Error("O3EInt.encode(): offset!=0 not implemented yet");
+                throw new Error('O3EInt.encode(): offset!=0 not implemented yet');
             }
             let val = Math.round(eval(string_ascii) * this.scale);
             if ( (this.signed) && (val < 0) ) { val += Math.pow(2,8*this.byte_width); }
-            let string_bin = toByteArray(toHex(val, this.byte_width*2));
+            const string_bin = toByteArray(toHex(val, this.byte_width*2));
             return string_bin.reverse();
         }
     }
 
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
         return int2val(string_bin.slice(this.offset,this.offset+this.byte_width), 0, this.signed) / this.scale;
@@ -159,21 +156,21 @@ class O3EByteVal {
         this.offset = offset;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         } else {
             if (this.offset != 0) {
-                throw new Error("O3EByteVal.encode(): offset!=0 not implemented yet");
+                throw new Error('O3EByteVal.encode(): offset!=0 not implemented yet');
             }
-            let val = Math.round(eval(string_ascii));
-            let string_bin = toHex(val, this.string_len*2);
-            let bytes = toByteArray(string_bin);
+            const val = Math.round(eval(string_ascii));
+            const string_bin = toHex(val, this.string_len*2);
+            const bytes = toByteArray(string_bin);
             return bytes.reverse();
         }
     }
 
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
         let val = 0;
@@ -195,18 +192,18 @@ class  O3EBool {
         this.offset = offset;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("O3EBool.encode(): not implemented yet");
+        throw new Error('O3EBool.encode(): not implemented yet');
     }
 
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        let val = string_bin[this.offset];
-        return (val == 0 ? "off" : "on" );
+        const val = string_bin[this.offset];
+        return (val == 0 ? 'off' : 'on' );
     }
 
     __len__() {
@@ -221,17 +218,18 @@ class O3EUtf8 {
         this.offset = offset;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        var mystr = '';
-        for (var i=this.offset; i<this.offset+this.string_len;i++) { mystr += String.fromCharCode(string_bin[i]); }
+        let mystr = '';
+        for (let i=this.offset; i<this.offset+this.string_len;i++) { mystr += String.fromCharCode(string_bin[i]); }
+        // eslint-disable-next-line no-control-regex
         return mystr.replace(/[\u0000-\u0008,\u000A-\u001F,\u007F-\u00A0]+/g, '');
     }
 
@@ -246,20 +244,20 @@ class O3ESoftVers {
         this.id = idStr;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        let lstv = [];
+        const lstv = [];
         for (let i = 0; i < this.string_len; i += 2) {
             lstv.push(string_bin[i] + (string_bin[i+1] << 8));
         }
-        return lstv.join(".");
+        return lstv.join('.');
     }
     __len__() {
         return this.string_len;
@@ -272,20 +270,20 @@ class O3EMacAddr {
         this.id = idStr;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        let lstv = [];
+        const lstv = [];
         for (let i = 0; i < this.string_len; i++) {
             lstv.push(toHex(string_bin[i],2).toUpperCase());
         }
-        return lstv.join("-");
+        return lstv.join('-');
     }
     __len__() {
         return this.string_len;
@@ -298,20 +296,20 @@ class O3EIp4Addr {
         this.id = idStr;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        let lstv = [];
+        const lstv = [];
         for (let i = 0; i < this.string_len; i++) {
             lstv.push(string_bin[i].toString().padStart(3,'0'));
         }
-        return lstv.join(".");
+        return lstv.join('.');
     }
     __len__() {
         return this.string_len;
@@ -324,22 +322,22 @@ class O3ESdate {
         this.id = idStr;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        var dt = new Date(
-                string_bin[2]+2000,     // year
-                string_bin[1]-1,        // month
-                string_bin[0]           // day
-                );
+        const dt = new Date(
+            string_bin[2]+2000,     // year
+            string_bin[1]-1,        // month
+            string_bin[0]           // day
+        );
         return dt.toLocaleDateString();
-  }
+    }
     __len__() {
         return this.string_len;
     }
@@ -351,23 +349,23 @@ class O3EStime {
         this.id = idStr;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        var now = new Date();
-        var dt = new Date(now.getFullYear(), now.getMonth(), now.getDate(),
-                string_bin[0],                                     // hour
-                ((this.string_len >= 2) ? string_bin[1] : 0),      // minute
-                ((this.string_len >= 3) ? string_bin[2] : 0)       // second
-                );
+        const now = new Date();
+        const dt = new Date(now.getFullYear(), now.getMonth(), now.getDate(),
+            string_bin[0],                                     // hour
+            ((this.string_len >= 2) ? string_bin[1] : 0),      // minute
+            ((this.string_len >= 3) ? string_bin[2] : 0)       // second
+        );
         return dt.toLocaleTimeString();
-  }
+    }
     __len__() {
         return this.string_len;
     }
@@ -380,16 +378,16 @@ class O3EDateTime {
         this.timeformat = timeformat;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        var dt = new Date();
+        let dt = new Date();
         if (this.timeformat == 'VM') {
             dt = new Date(
                 string_bin[0]*100+string_bin[1], // year
@@ -398,14 +396,14 @@ class O3EDateTime {
                 string_bin[5],                   // hour
                 string_bin[6],                   // minute
                 string_bin[7]                    // second
-               );
-       }
+            );
+        }
         if (this.timeformat == 'ts') {
             dt = new Date(uint32toVal(string_bin.slice(0,4),0)*1000);
         }
-        return { "DateTime": dt.toLocaleString(),
-                 "Timestamp": Math.round(dt.getTime())
-               }
+        return { 'DateTime': dt.toLocaleString(),
+            'Timestamp': Math.round(dt.getTime())
+        };
     }
     __len__() {
         return this.string_len;
@@ -418,16 +416,16 @@ class O3EUtc {
         this.id = idStr;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        var dt = new Date(uint32toVal(string_bin.slice(0,4),0)*1000);
+        const dt = new Date(uint32toVal(string_bin.slice(0,4),0)*1000);
         return dt.toUTCString();
     }
     __len__() {
@@ -442,24 +440,24 @@ class O3EEnum {
         this.listStr = listStr;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        var val = int2val(string_bin);
-        var txt = '';
+        const val = int2val(string_bin);
+        let txt = '';
         if ( (this.listStr in enums.enums) && (String(val) in enums.enums[this.listStr]) ) {
             txt = enums.enums[this.listStr][String(val)];
         } else {
-            txt = "Enum not found in " + this.listStr;
+            txt = 'Enum not found in ' + this.listStr;
         }
-        return {"ID": val,
-                "Text": txt }
+        return {'ID': val,
+            'Text': txt };
     }
     __len__() {
         return this.string_len;
@@ -473,29 +471,29 @@ class O3EList {
         this.subTypes = subTypes;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        var result = {};
-        var index = 0;
-        var count = 0;
-        for (var subType in this.subTypes) {
-            var subT = this.subTypes[subType];
+        const result = {};
+        let index = 0;
+        let count = 0;
+        for (const subType in this.subTypes) {
+            const subT = this.subTypes[subType];
             if (subT.id.toLowerCase() == 'count') {
                 count = subT.decode(string_bin.slice(index,index+subT.string_len));
                 result[subT.id]=count;
                 index += subT.string_len;
             } else {
-                if (("subTypes" in subT)) {
+                if (('subTypes' in subT)) {
                     // O3EComplexType
                     result[subT.id] = [];
-                    for (var i=0; i<count; i++) {
+                    for (let i=0; i<count; i++) {
                         result[subT.id].push(subT.decode(string_bin.slice(index,index+subT.string_len)));
                         index += subT.string_len;
                     }
@@ -506,7 +504,7 @@ class O3EList {
             }
         }
         return result;
-   }
+    }
     __len__() {
         return this.string_len;
     }
@@ -519,23 +517,23 @@ class O3EComplexType {
         this.subTypes = subTypes;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
-        var result = {};
-        var index = 0;
-        for (var subType in this.subTypes) {
+        const result = {};
+        let index = 0;
+        for (const subType in this.subTypes) {
             result[this.subTypes[subType].id] = this.subTypes[subType].decode(string_bin.slice(index,index+this.subTypes[subType].string_len));
             index+=this.subTypes[subType].string_len;
         }
         return result;
-   }
+    }
     __len__() {
         return this.string_len;
     }
@@ -548,20 +546,20 @@ class O3ECompStat {
         this.subTypes = subTypes;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
         return {
-            "starts": uint16toVal(string_bin.slice(6,8)),
-            "hours": uint16toVal(string_bin.slice(10,12))
-        }
-   }
+            'starts': uint16toVal(string_bin.slice(6,8)),
+            'hours': uint16toVal(string_bin.slice(10,12))
+        };
+    }
     __len__() {
         return this.string_len;
     }
@@ -574,20 +572,20 @@ class O3EAddElHeaterStat {
         this.subTypes = subTypes;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
         return {
-            "starts": uint16toVal(string_bin.slice(3,5)),
-            "hours": uint16toVal(string_bin.slice(7,9))
-        }
-   }
+            'starts': uint16toVal(string_bin.slice(3,5)),
+            'hours': uint16toVal(string_bin.slice(7,9))
+        };
+    }
     __len__() {
         return this.string_len;
     }
@@ -599,20 +597,20 @@ class O3EHeatingCurve {
         this.id = idStr;
     }
     encode(string_ascii) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawEncode(string_ascii, this.string_len);
         }
-        throw new Error("not implemented yet");
+        throw new Error('not implemented yet');
     }
     decode(string_bin) {
-        if (flag_rawmode == true) {
+        if (flag_rawmode) {
             return RawDecode(string_bin);
         }
         return {
-            "slope": uint08toVal([string_bin[0]])/10.0,
-            "offset": sint08toVal([string_bin[1]])
-        }
-   }
+            'slope': uint08toVal([string_bin[0]])/10.0,
+            'offset': sint08toVal([string_bin[1]])
+        };
+    }
     __len__() {
         return this.string_len;
     }
@@ -639,5 +637,4 @@ module.exports = {
     O3ECompStat,
     O3EAddElHeaterStat,
     O3EHeatingCurve
-  };
-  
\ No newline at end of file
+};