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

visitFunction(node) {
        var i, iz;
        // FunctionDeclaration name is defined in upper scope
        // NOTE: Not referring variableScope. It is intended.
        // Since
        //  in ES5, FunctionDeclaration should be in FunctionBody.
        //  in ES6, FunctionDeclaration should be block scoped.
        if (node.type === Syntax.FunctionDeclaration) {
            // id is defined in upper scope
            this.currentScope().__define(node.id,
                    new Definition(
                        Variable.FunctionName,
                        node.id,
                        node,
                        null,
                        null,
                        null
                    ));
        }

        // FunctionExpression with name creates its special scope;
        // FunctionExpressionNameScope.
        if (node.type === Syntax.FunctionExpression && node.id) {
            this.scopeManager.__nestFunctionExpressionNameScope(node);

public visitFunction(node: ESTree.Function) {
    let i: number, iz: number;

    // FunctionDeclaration name is defined in upper scope
    // NOTE: Not referring variableScope. It is intended.
    // Since
    //  in ES5, FunctionDeclaration should be in FunctionBody.
    //  in ES6, FunctionDeclaration should be block scoped.

    if (node.type === Syntax.FunctionDeclaration) {
      // id is defined in upper scope
      this.currentScope!.__define(
        node.id!,
        new Definition(
          VariableType.FunctionName,
          node.id!,
          node,
        ),
      );
    }

    // FunctionExpression with name creates its special scope;
    // FunctionExpressionNameScope.
    if (node.type === Syntax.FunctionExpression && node.id) {
      this.scopeManager.__nestFunctionExpressionNameScope(node);
    }

visitFunction(node) {
        let i, iz;

        // FunctionDeclaration name is defined in upper scope
        // NOTE: Not referring variableScope. It is intended.
        // Since
        //  in ES5, FunctionDeclaration should be in FunctionBody.
        //  in ES6, FunctionDeclaration should be block scoped.

        if (node.type === Syntax.FunctionDeclaration) {

            // id is defined in upper scope
            this.currentScope().__define(node.id,
                    new Definition(
                        Variable.FunctionName,
                        node.id,
                        node,
                        null,
                        null,
                        null
                    ));
        }

        // FunctionExpression with name creates its special scope;
        // FunctionExpressionNameScope.
        if (node.type === Syntax.FunctionExpression && node.id) {

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

                var i, iz;
                // FunctionDeclaration name is defined in upper scope
                // NOTE: Not referring variableScope. It is intended.
                // Since
                //  in ES5, FunctionDeclaration should be in FunctionBody.
                //  in ES6, FunctionDeclaration should be block scoped.
                if (node.type === Syntax.FunctionDeclaration) {
                    // id is defined in upper scope
                    this.currentScope().__define(node.id, new Definition(Variable.FunctionName, node.id, node, null, null, null));
                }

                // FunctionExpression with name creates its special scope;
                // FunctionExpressionNameScope.
                if (node.type === Syntax.FunctionExpression && node.id) {
                    this.scopeManager.__nestFunctionExpressionNameScope(node);
                }

                // Consider this function is in the MethodDefinition.
                this.scopeManager.__nestFunctionScope(node, this.isInnerMethodDefinition);

                // Process parameter declarations.
                for (i = 0, iz = node.params.length; i < iz; ++i) {
                    this.visitPattern(node.params[i], { processRightHandNodes: true }, function (pattern, info) {

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

                var i, iz;
                // FunctionDeclaration name is defined in upper scope
                // NOTE: Not referring variableScope. It is intended.
                // Since
                //  in ES5, FunctionDeclaration should be in FunctionBody.
                //  in ES6, FunctionDeclaration should be block scoped.
                if (node.type === Syntax.FunctionDeclaration) {
                    // id is defined in upper scope
                    this.currentScope().__define(node.id, new Definition(Variable.FunctionName, node.id, node, null, null, null));
                }

                // FunctionExpression with name creates its special scope;
                // FunctionExpressionNameScope.
                if (node.type === Syntax.FunctionExpression && node.id) {
                    this.scopeManager.__nestFunctionExpressionNameScope(node);
                }

                // Consider this function is in the MethodDefinition.
                this.scopeManager.__nestFunctionScope(node, this.isInnerMethodDefinition);

                // Process parameter declarations.
                for (i = 0, iz = node.params.length; i < iz; ++i) {
                    this.visitPattern(node.params[i], { processRightHandNodes: true }, function (pattern, info) {

visitFunction(node) {
        let i, iz;

        // FunctionDeclaration name is defined in upper scope
        // NOTE: Not referring variableScope. It is intended.
        // Since
        //  in ES5, FunctionDeclaration should be in FunctionBody.
        //  in ES6, FunctionDeclaration should be block scoped.

        if (node.type === Syntax.FunctionDeclaration) {

            // id is defined in upper scope
            this.currentScope().__define(node.id,
                    new Definition(
                        Variable.FunctionName,
                        node.id,
                        node,
                        null,
                        null,
                        null
                    ));
        }

        // FunctionExpression with name creates its special scope;
        // FunctionExpressionNameScope.
        if (node.type === Syntax.FunctionExpression && node.id) {

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

                var i, iz;
                // FunctionDeclaration name is defined in upper scope
                // NOTE: Not referring variableScope. It is intended.
                // Since
                //  in ES5, FunctionDeclaration should be in FunctionBody.
                //  in ES6, FunctionDeclaration should be block scoped.
                if (node.type === Syntax.FunctionDeclaration) {
                    // id is defined in upper scope
                    this.currentScope().__define(node.id, new Definition(Variable.FunctionName, node.id, node, null, null, null));
                }

                // FunctionExpression with name creates its special scope;
                // FunctionExpressionNameScope.
                if (node.type === Syntax.FunctionExpression && node.id) {
                    this.scopeManager.__nestFunctionExpressionNameScope(node);
                }

                // Consider this function is in the MethodDefinition.
                this.scopeManager.__nestFunctionScope(node, this.isInnerMethodDefinition);

                // Process parameter declarations.
                for (i = 0, iz = node.params.length; i < iz; ++i) {
                    this.visitPattern(node.params[i], { processRightHandNodes: true }, function (pattern, info) {

visitFunction(node) {
        var i, iz;
        // FunctionDeclaration name is defined in upper scope
        // NOTE: Not referring variableScope. It is intended.
        // Since
        //  in ES5, FunctionDeclaration should be in FunctionBody.
        //  in ES6, FunctionDeclaration should be block scoped.
        if (node.type === Syntax.FunctionDeclaration) {
            // id is defined in upper scope
            this.currentScope().__define(node.id,
                    new Definition(
                        Variable.FunctionName,
                        node.id,
                        node,
                        null,
                        null,
                        null
                    ));
        }

        // FunctionExpression with name creates its special scope;
        // FunctionExpressionNameScope.
        if (node.type === Syntax.FunctionExpression && node.id) {
            this.scopeManager.__nestFunctionExpressionNameScope(node);

visitFunction(node) {
        let i, iz;

        // FunctionDeclaration name is defined in upper scope
        // NOTE: Not referring variableScope. It is intended.
        // Since
        //  in ES5, FunctionDeclaration should be in FunctionBody.
        //  in ES6, FunctionDeclaration should be block scoped.

        if (node.type === Syntax.FunctionDeclaration) {

            // id is defined in upper scope
            this.currentScope().__define(node.id,
                new Definition(
                    Variable.FunctionName,
                    node.id,
                    node,
                    null,
                    null,
                    null
                ));
        }

        // FunctionExpression with name creates its special scope;
        // FunctionExpressionNameScope.
        if (node.type === Syntax.FunctionExpression && node.id) {

leave: function(node, parent, controller) {
            var lines = this.lines;
            switch(node.type) {
                case Syntax.FunctionDeclaration:
                    lines.appendLine("}");
            }
        }