motion/node_modules/sb-promisify/lib/index.js

motion - moving development forward

'use strict';

/* @flow */

module.exports = function promisify(callback) {
  return function promisified() {
    var _this = this;

    const parameters = Array.from(arguments);
    const parametersLength = parameters.length + 1;
    return new Promise(function (resolve, reject) {
      parameters.push(function (error, data) {
        if (error) {
          reject(error);
        } else resolve(data);
      });
      if (parametersLength === 1) {
        callback.call(_this, parameters[0]);
      } else if (parametersLength === 2) {
        callback.call(_this, parameters[0], parameters[1]);
      } else if (parametersLength === 3) {
        callback.call(_this, parameters[0], parameters[1], parameters[2]);
      } else if (parametersLength === 4) {
        callback.call(_this, parameters[0], parameters[1], parameters[2], parameters[3]);
      } else {
        callback.apply(_this, parameters);
      }
    });
  };
};