How to use the esrecurse.Visitor function in esrecurse

var visitor = new PatternVisitor(options, rootPattern, callback);
    visitor.visit(rootPattern);

    // Process the right hand nodes recursively.
    if (referencer != null) {
        visitor.rightHandNodes.forEach(referencer.visit, referencer);
    }
}

// Importing ImportDeclaration.
// http://people.mozilla.org/~jorendorff/es6-draft.html#sec-moduledeclarationinstantiation
// https://github.com/estree/estree/blob/master/es6.md#importdeclaration
// FIXME: Now, we don't create module environment, because the context is
// implementation dependent.

class Importer extends esrecurse.Visitor {
    constructor(declaration, referencer) {
        super(null, referencer.options);
        this.declaration = declaration;
        this.referencer = referencer;
    }

    visitImport(id, specifier) {
        this.referencer.visitPattern(id, (pattern) => {
            this.referencer.currentScope().__define(pattern,
                new Definition(
                    Variable.ImportBinding,
                    pattern,
                    specifier,
                    this.declaration,
                    null,
                    null

visitor.visit(rootPattern);

    // Process the right hand nodes recursively.
    if (referencer !== null && referencer !== undefined) {
        visitor.rightHandNodes.forEach(referencer.visit, referencer);
    }
}

// Importing ImportDeclaration.
// http://people.mozilla.org/~jorendorff/es6-draft.html#sec-moduledeclarationinstantiation
// https://github.com/estree/estree/blob/master/es6.md#importdeclaration
// FIXME: Now, we don't create module environment, because the context is
// implementation dependent.

class Importer extends esrecurse.Visitor {
    constructor(declaration, referencer) {
        super(null, referencer.options);
        this.declaration = declaration;
        this.referencer = referencer;
    }

    visitImport(id, specifier) {
        this.referencer.visitPattern(id, pattern => {
            this.referencer.currentScope().__define(pattern,
                new Definition(
                    Variable.ImportBinding,
                    pattern,
                    specifier,
                    this.declaration,
                    null,
                    null

visitor.visit(rootPattern);

    // Process the right hand nodes recursively.
    if (referencer !== null && referencer !== undefined) {
        visitor.rightHandNodes.forEach(referencer.visit, referencer);
    }
}

// Importing ImportDeclaration.
// http://people.mozilla.org/~jorendorff/es6-draft.html#sec-moduledeclarationinstantiation
// https://github.com/estree/estree/blob/master/es6.md#importdeclaration
// FIXME: Now, we don't create module environment, because the context is
// implementation dependent.

class Importer extends esrecurse.Visitor {
    constructor(declaration, referencer) {
        super(null, referencer.options);
        this.declaration = declaration;
        this.referencer = referencer;
    }

    visitImport(id, specifier) {
        this.referencer.visitPattern(id, pattern => {
            this.referencer.currentScope().__define(pattern,
                new Definition(
                    Variable.ImportBinding,
                    pattern,
                    specifier,
                    this.declaration,
                    null,
                    null

visitor.visit(rootPattern);

    // Process the right hand nodes recursively.
    if (referencer !== null && referencer !== undefined) {
        visitor.rightHandNodes.forEach(referencer.visit, referencer);
    }
}

// Importing ImportDeclaration.
// http://people.mozilla.org/~jorendorff/es6-draft.html#sec-moduledeclarationinstantiation
// https://github.com/estree/estree/blob/master/es6.md#importdeclaration
// FIXME: Now, we don't create module environment, because the context is
// implementation dependent.

class Importer extends esrecurse.Visitor {
    constructor(declaration, referencer) {
        super(null, referencer.options);
        this.declaration = declaration;
        this.referencer = referencer;
    }

    visitImport(id, specifier) {
        this.referencer.visitPattern(id, pattern => {
            this.referencer.currentScope().__define(pattern,
                new Definition(
                    Variable.ImportBinding,
                    pattern,
                    specifier,
                    this.declaration,
                    null,
                    null

visitor.visit(rootPattern);

    // Process the right hand nodes recursively.
    if (referencer !== null && referencer !== undefined) {
        visitor.rightHandNodes.forEach(referencer.visit, referencer);
    }
}

// Importing ImportDeclaration.
// http://people.mozilla.org/~jorendorff/es6-draft.html#sec-moduledeclarationinstantiation
// https://github.com/estree/estree/blob/master/es6.md#importdeclaration
// FIXME: Now, we don't create module environment, because the context is
// implementation dependent.

class Importer extends esrecurse.Visitor {
    constructor(declaration, referencer) {
        super(null, referencer.options);
        this.declaration = declaration;
        this.referencer = referencer;
    }

    visitImport(id, specifier) {
        this.referencer.visitPattern(id, pattern => {
            this.referencer.currentScope().__define(pattern,
                new Definition(
                    Variable.ImportBinding,
                    pattern,
                    specifier,
                    this.declaration,
                    null,
                    null

public ImportSpecifier(node: ESTree.ImportSpecifier) {
    const local = node.local;

    this.visitImport(local, node);
    const importId = new ImportIdentifierInfo(
      local.name,
      node.imported.name,
      this.declaration.source.value as string,
      ImportType.Identifier,
    );
    this.moduleScope.importManager.addImportId(importId);
  }
}

// Referencing variables and creating bindings.
export class Referencer extends esrecurse.Visitor {
  public parent: Referencer | null = null;
  public isInnerMethodDefinition: boolean = false;
  public exportingSource: string | null = null;
  public isExportingFromLocal: boolean = false;

  public constructor(
    public readonly options: esrecurse.VisitorOption,
    public readonly scopeManager: ScopeManager,
  ) {
    super(undefined, options);
  }

  get currentScope() {
    return this.scopeManager.__currentScope;
  }

this.visitImport(local, node);
    }

    ImportSpecifier(node) {
        const local = (node.local || node.id);

        if (node.name) {
            this.visitImport(node.name, node);
        } else {
            this.visitImport(local, node);
        }
    }
}

// Referencing variables and creating bindings.
class Referencer extends esrecurse.Visitor {
    constructor(options, scopeManager) {
        super(null, options);
        this.options = options;
        this.scopeManager = scopeManager;
        this.parent = null;
        this.isInnerMethodDefinition = false;
    }

    currentScope() {
        return this.scopeManager.__currentScope;
    }

    close(node) {
        while (this.currentScope() && node === this.currentScope().block) {
            this.scopeManager.__currentScope = this.currentScope().__close(this.scopeManager);
        }

this.visitImport(local, node);
    }

    ImportSpecifier(node) {
        const local = (node.local || node.id);

        if (node.name) {
            this.visitImport(node.name, node);
        } else {
            this.visitImport(local, node);
        }
    }
}

// Referencing variables and creating bindings.
class Referencer extends esrecurse.Visitor {
    constructor(options, scopeManager) {
        super(null, options);
        this.options = options;
        this.scopeManager = scopeManager;
        this.parent = null;
        this.isInnerMethodDefinition = false;
    }

    currentScope() {
        return this.scopeManager.__currentScope;
    }

    close(node) {
        while (this.currentScope() && node === this.currentScope().block) {
            this.scopeManager.__currentScope = this.currentScope().__close(this.scopeManager);
        }

DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

import { Syntax } from 'estraverse';
import esrecurse from 'esrecurse';

function getLast(xs) {
    return xs[xs.length - 1] || null;
}

export default class PatternVisitor extends esrecurse.Visitor {
    static isPattern(node) {
        var nodeType = node.type;
        return (
            nodeType === Syntax.Identifier ||
            nodeType === Syntax.ObjectPattern ||
            nodeType === Syntax.ArrayPattern ||
            nodeType === Syntax.SpreadElement ||
            nodeType === Syntax.RestElement ||
            nodeType === Syntax.AssignmentPattern
        );
    }

    constructor(options, rootPattern, callback) {
        super(null, options);
        this.rootPattern = rootPattern;
        this.callback = callback;

export type AssignmentType =
  | ESTree.AssignmentPattern
  | ESTree.AssignmentExpression;

export interface ICallbackOption {
  topLevel: boolean;
  rest: boolean;
  assignments: AssignmentType[];
}

export type PatternVisitorCallback = (
  id: ESTree.Identifier,
  option: ICallbackOption,
) => void;

export class PatternVisitor extends esrecurse.Visitor {
  public static isPattern(node: ESTree.Node) {
    const nodeType = node.type;

    return (
      nodeType === Syntax.Identifier ||
      nodeType === Syntax.ObjectPattern ||
      nodeType === Syntax.ArrayPattern ||
      nodeType === Syntax.SpreadElement ||
      nodeType === Syntax.RestElement ||
      nodeType === Syntax.AssignmentPattern
    );
  }

  public rootPattern: any;
  public callback: PatternVisitorCallback;
  public assignments: AssignmentType[];