pouchdb-mapreduce-utils/lib/index.es.js

PouchDB utilities used by pouchdb-mapreduce.

import { nextTick } from 'pouchdb-utils';

class QueryParseError extends Error {
  constructor(message) {
    super();
    this.status = 400;
    this.name = 'query_parse_error';
    this.message = message;
    this.error = true;
    try {
      Error.captureStackTrace(this, QueryParseError);
    } catch (e) {}
  }
}

class NotFoundError extends Error {
  constructor(message) {
    super();
    this.status = 404;
    this.name = 'not_found';
    this.message = message;
    this.error = true;
    try {
      Error.captureStackTrace(this, NotFoundError);
    } catch (e) {}
  }
}

class BuiltInError extends Error {
  constructor(message) {
    super();
    this.status = 500;
    this.name = 'invalid_value';
    this.message = message;
    this.error = true;
    try {
      Error.captureStackTrace(this, BuiltInError);
    } catch (e) {}
  }
}

function promisedCallback(promise, callback) {
  if (callback) {
    promise.then(function (res) {
      nextTick(function () {
        callback(null, res);
      });
    }, function (reason) {
      nextTick(function () {
        callback(reason);
      });
    });
  }
  return promise;
}

function callbackify(fun) {
  return function (...args) {
    var cb = args.pop();
    var promise = fun.apply(this, args);
    if (typeof cb === 'function') {
      promisedCallback(promise, cb);
    }
    return promise;
  };
}

// Promise finally util similar to Q.finally
function fin(promise, finalPromiseFactory) {
  return promise.then(function (res) {
    return finalPromiseFactory().then(function () {
      return res;
    });
  }, function (reason) {
    return finalPromiseFactory().then(function () {
      throw reason;
    });
  });
}

function sequentialize(queue, promiseFactory) {
  return function () {
    var args = arguments;
    var that = this;
    return queue.add(function () {
      return promiseFactory.apply(that, args);
    });
  };
}

// uniq an array of strings, order not guaranteed
// similar to underscore/lodash _.uniq
function uniq(arr) {
  var theSet = new Set(arr);
  var result = new Array(theSet.size);
  var index = -1;
  theSet.forEach(function (value) {
    result[++index] = value;
  });
  return result;
}

function mapToKeysArray(map) {
  var result = new Array(map.size);
  var index = -1;
  map.forEach(function (value, key) {
    result[++index] = key;
  });
  return result;
}

export { uniq, sequentialize, fin, callbackify, promisedCallback, mapToKeysArray, QueryParseError, NotFoundError, BuiltInError };