oas-validator

Usage:

const validator = require('oas-validator');
const options = {};
validator.validate(openapi, options, function(err, options){
  // options.valid contains the result of the validation
  // options.context now contains a stack (array) of JSON-Pointer strings
});

If the callback argument of validate is omitted, a Promise is returned instead.

See here for complete documentation of the options object.