mimus-mocker/lib/index.js

MimusMocker is a unified API mocking middleware which can be used for providing API mocks quickly i.e even before writing a single line of actual api into your [Routers](https://expressjs.com/en/guide/routing.html).

/**
 * Created by ajay.meher on 28/06/17.
 */
'use strict';

const matchPattern = require('url-matcher').matchPattern;

module.exports = function (options) {

  return function _mimusMocker(req, res, next) {
    if (!options
      || !options.isEligible
      || (options.mocks && !Array.isArray(options.mocks)))
      return next();

    let shouldWait = false;

    for (let i = 0; i < options.mocks.length; i++) {
      let result;
      const mock = options.mocks[i];

      if (!(mock && mock.isEligible
        && req.method === mock.method)) {
        continue;
      }

      let matchedResult = matchPattern(mock.url, req.originalUrl);

      if (!matchedResult) {
        continue;
      }

      if (matchedResult.paramNames && matchedResult.paramNames.length > 0) {
        _embedParams(req, matchedResult);
      }

      result = mock.responseData || {};

      if (!mock.additionalValidator) {
        return res.status(200).json(result);
      }

      shouldWait = true;
      mock.additionalValidator(req, res, function (overrideResult, updatedRes) {
        return overrideResult ? updatedRes : res.status(200).json(result);
      });
      break;
    }
    if (!shouldWait) next();
  }
};

// embed params as user might have applied Mimus directly.
function _embedParams(req, matchedResult) {
  if (!matchedResult) {
    return;
  }

  if (matchedResult.paramNames && matchedResult.paramNames.length > 0) {
    for (let i = 0; i < matchedResult.paramNames.length; i++) {
      req.params[matchedResult.paramNames[i] + ""] = matchedResult.paramValues[i];
    }
  }

  if (matchedResult.remainingPathname) {
    req.remainingPath = matchedResult.remainingPathname;
  }
}