https://www.graalvm.org/ 
public abstract class com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode extends com.oracle.truffle.js.builtins.NumberPrototypeBuiltins$JSNumberOperation
  minor version: 0
  major version: 59
  flags: flags: (0x0421) ACC_PUBLIC, ACC_SUPER, ACC_ABSTRACT
  this_class: com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode
  super_class: com.oracle.truffle.js.builtins.NumberPrototypeBuiltins$JSNumberOperation
{
  private com.oracle.truffle.js.nodes.cast.JSToUInt16Node toUInt16Node;
    descriptor: Lcom/oracle/truffle/js/nodes/cast/JSToUInt16Node;
    flags: (0x0002) ACC_PRIVATE
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.nodes.Node$Child()

  public void <init>(com.oracle.truffle.js.runtime.JSContext, com.oracle.truffle.js.nodes.function.JSBuiltin);
    descriptor: (Lcom/oracle/truffle/js/runtime/JSContext;Lcom/oracle/truffle/js/nodes/function/JSBuiltin;)V
    flags: (0x0001) ACC_PUBLIC
    Code:
      stack=3, locals=3, args_size=3
        start local 0 // com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode this
        start local 1 // com.oracle.truffle.js.runtime.JSContext context
        start local 2 // com.oracle.truffle.js.nodes.function.JSBuiltin builtin
         0: .line 122
            aload 0 /* this */
            aload 1 /* context */
            aload 2 /* builtin */
            invokespecial com.oracle.truffle.js.builtins.NumberPrototypeBuiltins$JSNumberOperation.<init>:(Lcom/oracle/truffle/js/runtime/JSContext;Lcom/oracle/truffle/js/nodes/function/JSBuiltin;)V
         1: .line 123
            return
        end local 2 // com.oracle.truffle.js.nodes.function.JSBuiltin builtin
        end local 1 // com.oracle.truffle.js.runtime.JSContext context
        end local 0 // com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode this
      LocalVariableTable:
        Start  End  Slot     Name  Signature
            0    2     0     this  Lcom/oracle/truffle/js/builtins/StringFunctionBuiltins$JSFromCharCodeNode;
            0    2     1  context  Lcom/oracle/truffle/js/runtime/JSContext;
            0    2     2  builtin  Lcom/oracle/truffle/js/nodes/function/JSBuiltin;
    MethodParameters:
         Name  Flags
      context  
      builtin  

  private char toChar(java.lang.Object);
    descriptor: (Ljava/lang/Object;)C
    flags: (0x0002) ACC_PRIVATE
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode this
        start local 1 // java.lang.Object target
         0: .line 128
            aload 0 /* this */
            getfield com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode.toUInt16Node:Lcom/oracle/truffle/js/nodes/cast/JSToUInt16Node;
            ifnonnull 3
         1: .line 129
            invokestatic com.oracle.truffle.api.CompilerDirectives.transferToInterpreterAndInvalidate:()V
         2: .line 130
            aload 0 /* this */
            aload 0 /* this */
            invokestatic com.oracle.truffle.js.nodes.cast.JSToUInt16Node.create:()Lcom/oracle/truffle/js/nodes/cast/JSToUInt16Node;
            invokevirtual com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode.insert:(Lcom/oracle/truffle/api/nodes/Node;)Lcom/oracle/truffle/api/nodes/Node;
            checkcast com.oracle.truffle.js.nodes.cast.JSToUInt16Node
            putfield com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode.toUInt16Node:Lcom/oracle/truffle/js/nodes/cast/JSToUInt16Node;
         3: .line 132
      StackMap locals:
      StackMap stack:
            aload 0 /* this */
            getfield com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode.toUInt16Node:Lcom/oracle/truffle/js/nodes/cast/JSToUInt16Node;
            aload 1 /* target */
            invokevirtual com.oracle.truffle.js.nodes.cast.JSToUInt16Node.executeInt:(Ljava/lang/Object;)I
            i2c
            ireturn
        end local 1 // java.lang.Object target
        end local 0 // com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    4     0    this  Lcom/oracle/truffle/js/builtins/StringFunctionBuiltins$JSFromCharCodeNode;
            0    4     1  target  Ljava/lang/Object;
    MethodParameters:
        Name  Flags
      target  

  protected java.lang.String fromCharCode(java.lang.Object[]);
    descriptor: ([Ljava/lang/Object;)Ljava/lang/String;
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=1, locals=2, args_size=2
        start local 0 // com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode this
        start local 1 // java.lang.Object[] args
         0: .line 137
            ldc ""
            areturn
        end local 1 // java.lang.Object[] args
        end local 0 // com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/js/builtins/StringFunctionBuiltins$JSFromCharCodeNode;
            0    1     1  args  [Ljava/lang/Object;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.dsl.Specialization(guards = {"args.length == 0"})
    MethodParameters:
      Name  Flags
      args  

  protected java.lang.String fromCharCodeOneArg(java.lang.Object[]);
    descriptor: ([Ljava/lang/Object;)Ljava/lang/String;
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=3, locals=2, args_size=2
        start local 0 // com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode this
        start local 1 // java.lang.Object[] args
         0: .line 142
            aload 0 /* this */
            aload 1 /* args */
            iconst_0
            aaload
            invokevirtual com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode.toChar:(Ljava/lang/Object;)C
            invokestatic java.lang.String.valueOf:(C)Ljava/lang/String;
            areturn
        end local 1 // java.lang.Object[] args
        end local 0 // com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/truffle/js/builtins/StringFunctionBuiltins$JSFromCharCodeNode;
            0    1     1  args  [Ljava/lang/Object;
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.dsl.Specialization(guards = {"args.length == 1"})
    MethodParameters:
      Name  Flags
      args  

  protected java.lang.String fromCharCodeTwoOrMore(java.lang.Object[]);
    descriptor: ([Ljava/lang/Object;)Ljava/lang/String;
    flags: (0x0004) ACC_PROTECTED
    Code:
      stack=4, locals=4, args_size=2
        start local 0 // com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode this
        start local 1 // java.lang.Object[] args
         0: .line 147
            new java.lang.StringBuilder
            dup
            aload 1 /* args */
            arraylength
            iconst_4
            iadd
            invokespecial java.lang.StringBuilder.<init>:(I)V
            astore 2 /* buffer */
        start local 2 // java.lang.StringBuilder buffer
         1: .line 148
            iconst_0
            istore 3 /* i */
        start local 3 // int i
         2: goto 5
         3: .line 149
      StackMap locals: java.lang.StringBuilder int
      StackMap stack:
            aload 2 /* buffer */
            aload 0 /* this */
            aload 1 /* args */
            iload 3 /* i */
            aaload
            invokevirtual com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode.toChar:(Ljava/lang/Object;)C
            invokestatic com.oracle.truffle.js.runtime.Boundaries.builderAppend:(Ljava/lang/StringBuilder;C)V
         4: .line 148
            iinc 3 /* i */ 1
      StackMap locals:
      StackMap stack:
         5: iload 3 /* i */
            aload 1 /* args */
            arraylength
            if_icmplt 3
        end local 3 // int i
         6: .line 151
            aload 2 /* buffer */
            invokestatic com.oracle.truffle.js.runtime.Boundaries.builderToString:(Ljava/lang/StringBuilder;)Ljava/lang/String;
            areturn
        end local 2 // java.lang.StringBuilder buffer
        end local 1 // java.lang.Object[] args
        end local 0 // com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode this
      LocalVariableTable:
        Start  End  Slot    Name  Signature
            0    7     0    this  Lcom/oracle/truffle/js/builtins/StringFunctionBuiltins$JSFromCharCodeNode;
            0    7     1    args  [Ljava/lang/Object;
            1    7     2  buffer  Ljava/lang/StringBuilder;
            2    6     3       i  I
    RuntimeVisibleAnnotations: 
      com.oracle.truffle.api.dsl.Specialization(guards = {"args.length >= 2"})
    MethodParameters:
      Name  Flags
      args  
}
SourceFile: "StringFunctionBuiltins.java"
NestHost: com.oracle.truffle.js.builtins.StringFunctionBuiltins
InnerClasses:
  public abstract Child = com.oracle.truffle.api.nodes.Node$Child of com.oracle.truffle.api.nodes.Node
  public abstract JSNumberOperation = com.oracle.truffle.js.builtins.NumberPrototypeBuiltins$JSNumberOperation of com.oracle.truffle.js.builtins.NumberPrototypeBuiltins
  public abstract JSFromCharCodeNode = com.oracle.truffle.js.builtins.StringFunctionBuiltins$JSFromCharCodeNode of com.oracle.truffle.js.builtins.StringFunctionBuiltins