Resolve comments

Author: dastanbeksamatov

assembly/Bool.ts

@@ -63,7 +63,7 @@ export class Bool implements Codec {
 
     /** Instantiates new Bool from u8[] SCALE encoded bytes */
     static fromU8a (value: u8[], index: i32 = 0): Bool {
-        assert(value.length > 0 && (value[index] == 1 || value[index] == 0), 'Bool: Cannot decode invalid input');
+        assert(value.length - index > 0 && (value[index] == 1 || value[index] == 0), 'Bool: Cannot decode invalid input');
 
         return new Bool(value[index] == 1);
     }

assembly/ScaleString.ts

@@ -69,7 +69,6 @@ export class ScaleString extends ByteArray {
         assert(bytes.length - index - len.decBytes >= 1, "ScaleString: Incorrectly encoded input");
         const buff = new Uint8Array(bytesLength);
         Bytes.copyToTyped(bytes, buff, 0, index+stringStart);
-        // constructor
         return String.UTF8.decode(buff.buffer);
     }
     /**

assembly/UInt/UInt128.ts

@@ -64,7 +64,7 @@ export class UInt128 implements Codec {
      */
     populateFromBytes(bytes: u8[], index: i32 = 0): void{
         assert(bytes.length - index > 0, 'Invalid input: Byte array should not be empty');
-        const value = UInt128._computeValue(bytes.slice(index));
+        const value = UInt128._computeValue(bytes, index);
         this._value = value;
         this.bitLength = UInt128._computeBitLength(this._value);
     }
@@ -80,15 +80,15 @@ export class UInt128 implements Codec {
      * @param bytes 
      * @param index 
      */
-    static _computeValue(bytes: u8[]): u128{
-        const mode = bytes[0] & 0x03;
+    static _computeValue(bytes: u8[], index: i32 = 0): u128{
+        const mode = bytes[index] & 0x03;
         if (i32(mode) <= 2) {
-            return new u128(u64(Bytes.decodeSmallInt(bytes, mode, 0).value), 0);
+            return new u128(u64(Bytes.decodeSmallInt(bytes, mode, index).value), 0);
         }
-        const topSixBits = bytes[0] >> 2;
+        const topSixBits = bytes[index] >> 2;
         const byteLength = topSixBits + 4;
 
-        const value = bytes.slice(1, byteLength + 1);
+        const value = bytes.slice(index + 1, byteLength + index + 1);
         Bytes.appendZeroBytes(value, BIT_LENGTH.INT_128);
         return u128.fromBytesLE(value)
     }
@@ -111,7 +111,7 @@ export class UInt128 implements Codec {
     /** Instantiates new UInt128 from u8[] SCALE encoded bytes */
     static fromU8a(input: u8[], index: i32 = 0): UInt128 {
         assert(input.length - index != 0, 'Invalid input: Byte array should not be empty');
-        return new UInt128(UInt128._computeValue(input.slice(index)));
+        return new UInt128(UInt128._computeValue(input, index));
     }
 
     @inline @operator('==')