JsVariableDeclaration.cs

using System;
using System.Collections.Generic;
using System.Linq;
using ServiceStack.Text;

namespace ServiceStack.Script 
{
    public class JsVariableDeclaration : JsExpression
    {
        public JsVariableDeclarationKind Kind { get; }
        public JsDeclaration[] Declarations { get; }

        public JsVariableDeclaration(JsVariableDeclarationKind kind, params JsDeclaration[] declarations)
        {
            Kind = kind;
            Declarations = declarations;
        }

        protected bool Equals(JsVariableDeclaration other) => 
            Kind == other.Kind && Declarations.SequenceEqual(other.Declarations);

        public override bool Equals(object obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            if (ReferenceEquals(this, obj)) return true;
            if (obj.GetType() != this.GetType()) return false;
            return Equals((JsVariableDeclaration) obj);
        }

        public override int GetHashCode()
        {
            unchecked
            {
                return ((int) Kind * 397) ^ (Declarations != null ? Declarations.GetHashCode() : 0);
            }
        }

        public override string ToRawString()
        {
            var sb = StringBuilderCache.Allocate();
            sb.Append(Kind.ToString().ToLower()).Append(" ");

            for (var i = 0; i < Declarations.Length; i++)
            {
                var dec = Declarations[i];
                if (i > 0)
                    sb.Append(", ");
                sb.Append(dec.ToRawString());
            }
            return StringBuilderCache.ReturnAndFree(sb);
        }

        public override object Evaluate(ScriptScopeContext scope)
        {
            foreach (var declaration in Declarations)
            {
                scope.ScopedParams[declaration.Id.Name] = declaration.Init?.Evaluate(scope);
            }
            return JsNull.Value;
        }

        public override Dictionary<string, object> ToJsAst()
        {
            var to = new Dictionary<string, object>
            {
                ["type"] = ToJsAstType(),
                ["declarations"] = Declarations.Map(x => (object)x.ToJsAst()),
                ["kind"] = Kind.ToString().ToLower(),
            };
            return to;
        }
    }
    

    public enum JsVariableDeclarationKind
    {
        Var,
        Let,
        Const,
    }

    public class JsDeclaration : JsExpression
    {
        public JsIdentifier Id { get; set; }
        
        public JsToken Init { get; set; }

        public JsDeclaration(JsIdentifier id, JsToken init)
        {
            Id = id;
            Init = init;
        }

        protected bool Equals(JsDeclaration other) => Equals(Id, other.Id) && Equals(Init, other.Init);

        public override bool Equals(object obj)
        {
            if (ReferenceEquals(null, obj)) return false;
            if (ReferenceEquals(this, obj)) return true;
            if (obj.GetType() != this.GetType()) return false;
            return Equals((JsDeclaration) obj);
        }

        public override int GetHashCode()
        {
            unchecked
            {
                return ((Id != null ? Id.GetHashCode() : 0) * 397) ^ (Init != null ? Init.GetHashCode() : 0);
            }
        }

        public override string ToRawString() => Init != null
            ? $"{Id.Name} = {Init.ToRawString()}"
            : Id.Name;

        public override object Evaluate(ScriptScopeContext scope)
        {
            throw new System.NotImplementedException();
        }

        public override Dictionary<string, object> ToJsAst()
        {
            var to = new Dictionary<string, object>
            {
                ["type"] = ToJsAstType(),
                ["id"] = Id.Name,
                ["init"] = Init?.ToJsAst(),
            };
            return to;
        }
    }    
}