errorManager.js

'use strict';

const _ = require('lodash');
const errors = [
  {
    code: 404,
    httpStatus: 404,
    errorTemplate: '${resourceName} resource not found'
  },
  {
    code: 11000,
    httpStatus: 409,
    errorTemplate: '${resourceName} already exists'
  },
  {
    code: 500,
    httpStatus: 500,
    errorTemplate: 'Oops! Something went wrong'
  }
];

/**
 * complies template string with placeholder
 * @param stringWithPlaceholder
 * @param context
 */
function compileTemplate (stringWithPlaceholder, context, options) {
  if (options) {
    _.templateSettings(options);
  }
  return _.template(stringWithPlaceholder)(context);
}

/**
 * Main error helper constructor
 * @constructor
 */
function ErrorHelper () {}


/**
 * finds error by code and compiles the final message using placeholder
 * @param code
 * @param msgPlaceholder
 * @returns {null}
 */
ErrorHelper.prototype.findByCode = function findErrorByCode (code, msgPlaceholder) {
  const error = _.find(errors, { code: code });
  if (!error) {
    return null;
  }
  let derivedError = new Error();
  derivedError.message = compileTemplate(error.errorTemplate, msgPlaceholder);
  derivedError.status = error.httpStatus;
  derivedError.code = error.code;
  return derivedError;
};
module.exports = new ErrorHelper();