How to use the estraverse.Syntax.VariableDeclaration function in estraverse

function handleInlineDeclaration(node, opt) {
        if(!node)
            return "";
        if (node.type == Syntax.VariableDeclaration) {
            var result = node.declarations.reduce(function (declString, declaration) {
                var decl = toOSLType(declaration.extra) + " " + declaration.id.name;
                if (declaration.init) {
                    decl += " = " + handler.expression(declaration.init);
                }
                return declString + decl;
            }, "");
            return result;
        }

        // GLSL allows only declaration in init, but since this is a new scope, it should be fine
        if (node.type == Syntax.AssignmentExpression) {
            return toOSLType(node.extra) + " " + handler.expression(node.left) + " = " + handler.expression(node.right);
        }
        Shade.throwError(node, "Internal error in GLSL::handleInlineDeclaration, found " + node.type);
    }

visitForIn(node) {
        if (node.left.type === Syntax.VariableDeclaration && node.left.kind !== "var") {
            this.materializeTDZScope(node.right, node);
            this.visit(node.right);
            this.close(node.right);

            this.materializeIterationScope(node);
            this.visit(node.body);
            this.close(node);
        } else {
            if (node.left.type === Syntax.VariableDeclaration) {
                this.visit(node.left);
                this.visitPattern(node.left.declarations[0].id, pattern => {
                    this.currentScope().__referencing(pattern, Reference.WRITE, node.right, null, true, true);
                });
            } else {
                this.visitPattern(node.left, { processRightHandNodes: true }, (pattern, info) => {
                    let maybeImplicitGlobal = null;

                    if (!this.currentScope().isStrict) {
                        maybeImplicitGlobal = {
                            pattern,
                            node
                        };
                    }
                    this.referencingDefaultValue(pattern, info.assignments, maybeImplicitGlobal, false);
                    this.currentScope().__referencing(pattern, Reference.WRITE, node.right, maybeImplicitGlobal, true, false);

visitForIn(node) {
        if (node.left.type === Syntax.VariableDeclaration && node.left.kind !== "var") {
            this.scopeManager.__nestForScope(node);
        }

        if (node.left.type === Syntax.VariableDeclaration) {
            this.visit(node.left);
            this.visitPattern(node.left.declarations[0].id, pattern => {
                this.currentScope().__referencing(pattern, Reference.WRITE, node.right, null, true, true);
            });
        } else {
            this.visitPattern(node.left, { processRightHandNodes: true }, (pattern, info) => {
                let maybeImplicitGlobal = null;

                if (!this.currentScope().isStrict) {
                    maybeImplicitGlobal = {
                        pattern,
                        node
                    };
                }
                this.referencingDefaultValue(pattern, info.assignments, maybeImplicitGlobal, false);
                this.currentScope().__referencing(pattern, Reference.WRITE, node.right, maybeImplicitGlobal, true, false);

value: function visitForIn(node) {
                var _this = this;

                if (node.left.type === Syntax.VariableDeclaration && node.left.kind !== "var") {
                    this.materializeTDZScope(node.right, node);
                    this.visit(node.right);
                    this.close(node.right);

                    this.materializeIterationScope(node);
                    this.visit(node.body);
                    this.close(node);
                } else {
                    if (node.left.type === Syntax.VariableDeclaration) {
                        this.visit(node.left);
                        this.visitPattern(node.left.declarations[0].id, function (pattern) {
                            _this.currentScope().__referencing(pattern, Reference.WRITE, node.right, null, true, true);
                        });
                    } else {
                        this.visitPattern(node.left, { processRightHandNodes: true }, function (pattern, info) {
                            var maybeImplicitGlobal = null;

visitForIn(node) {
        if (node.left.type === Syntax.VariableDeclaration && node.left.kind !== 'var') {
            this.materializeTDZScope(node.right, node);
            this.visit(node.right);
            this.close(node.right);

            this.materializeIterationScope(node);
            this.visit(node.body);
            this.close(node);
        } else {
            if (node.left.type === Syntax.VariableDeclaration) {
                this.visit(node.left);
                this.visitPattern(node.left.declarations[0].id, (pattern) => {
                    this.currentScope().__referencing(pattern, Reference.WRITE, node.right, null, true, true);
                });
            } else {
                this.visitPattern(node.left, {processRightHandNodes: true}, (pattern, info) => {
                    var maybeImplicitGlobal = null;
                    if (!this.currentScope().isStrict) {
                        maybeImplicitGlobal = {
                            pattern: pattern,
                            node: node
                        };
                    }
                    this.referencingDefaultValue(pattern, info.assignments, maybeImplicitGlobal, false);
                    this.currentScope().__referencing(pattern, Reference.WRITE, node.right, maybeImplicitGlobal, true, false);
                });

value: function visitForIn(node) {
                var _this = this;

                if (node.left.type === Syntax.VariableDeclaration && node.left.kind !== "var") {
                    this.materializeTDZScope(node.right, node);
                    this.visit(node.right);
                    this.close(node.right);

                    this.materializeIterationScope(node);
                    this.visit(node.body);
                    this.close(node);
                } else {
                    if (node.left.type === Syntax.VariableDeclaration) {
                        this.visit(node.left);
                        this.visitPattern(node.left.declarations[0].id, function (pattern) {
                            _this.currentScope().__referencing(pattern, Reference.WRITE, node.right, null, true, true);
                        });
                    } else {
                        this.visitPattern(node.left, { processRightHandNodes: true }, function (pattern, info) {
                            var maybeImplicitGlobal = null;

visitForIn(node) {
        if (node.left.type === Syntax.VariableDeclaration && node.left.kind !== "var") {
            this.materializeTDZScope(node.right, node);
            this.visit(node.right);
            this.close(node.right);

            this.materializeIterationScope(node);
            this.visit(node.body);
            this.close(node);
        } else {
            if (node.left.type === Syntax.VariableDeclaration) {
                this.visit(node.left);
                this.visitPattern(node.left.declarations[0].id, pattern => {
                    this.currentScope().__referencing(pattern, Reference.WRITE, node.right, null, true, true);
                });
            } else {
                this.visitPattern(node.left, { processRightHandNodes: true }, (pattern, info) => {
                    let maybeImplicitGlobal = null;

public visitForIn(
    node: ESTree.ForInStatement | ESTree.ForOfStatement,
  ) {
    if (
      node.left.type === Syntax.VariableDeclaration &&
      node.left.kind !== "var"
    ) {
      this.materializeTDZScope(node.right, node);
      this.visit(node.right);
      this.close(node.right);

      this.materializeIterationScope(node);
      this.visit(node.body);
      this.close(node);
    } else {
      if (node.left.type === Syntax.VariableDeclaration) {
        this.visit(node.left);
        this.visitPattern(
          node.left.declarations[0].id,
          undefined,
          pattern => {

visitForIn(node) {
        if (node.left.type === Syntax.VariableDeclaration && node.left.kind !== "var") {
            this.materializeTDZScope(node.right, node);
            this.visit(node.right);
            this.close(node.right);

            this.materializeIterationScope(node);
            this.visit(node.body);
            this.close(node);
        } else {
            if (node.left.type === Syntax.VariableDeclaration) {
                this.visit(node.left);
                this.visitPattern(node.left.declarations[0].id, pattern => {
                    this.currentScope().__referencing(pattern, Reference.WRITE, node.right, null, true, true);
                });
            } else {
                this.visitPattern(node.left, { processRightHandNodes: true }, (pattern, info) => {
                    let maybeImplicitGlobal = null;

value: function visitForIn(node) {
                var _this = this;

                if (node.left.type === Syntax.VariableDeclaration && node.left.kind !== "var") {
                    this.materializeTDZScope(node.right, node);
                    this.visit(node.right);
                    this.close(node.right);

                    this.materializeIterationScope(node);
                    this.visit(node.body);
                    this.close(node);
                } else {
                    if (node.left.type === Syntax.VariableDeclaration) {
                        this.visit(node.left);
                        this.visitPattern(node.left.declarations[0].id, function (pattern) {
                            _this.currentScope().__referencing(pattern, Reference.WRITE, node.right, null, true, true);
                        });
                    } else {
                        this.visitPattern(node.left, { processRightHandNodes: true }, function (pattern, info) {
                            var maybeImplicitGlobal = null;
                            if (!_this.currentScope().isStrict) {
                                maybeImplicitGlobal = {
                                    pattern: pattern,
                                    node: node
                                };
                            }
                            _this.referencingDefaultValue(pattern, info.assignments, maybeImplicitGlobal, false);
                            _this.currentScope().__referencing(pattern, Reference.WRITE, node.right, maybeImplicitGlobal, true, false);
                        });