1  let Promise = global.Promise;
 2  
 3  /// encapsulate a method with a node-style callback in a Promise
 4  /// @param {object} 'this' of the encapsulated function
 5  /// @param {function} function to be encapsulated
 6  /// @param {Array-like} args to be passed to the called function
 7  /// @return {Promise} a Promise encapsulating the function
 8  function promise(fn, context, args) {
 9      if (!Array.isArray(args)) {
10          args = Array.prototype.slice.call(args);
11      }
12  
13      if (typeof fn !== 'function') {
14          return Promise.reject(new Error('fn must be a function'));
15      }
16  
17      return new Promise((resolve, reject) => {
18          args.push((err, data) => {
19              if (err) {
20                  reject(err);
21              } else {
22                  resolve(data);
23              }
24          });
25  
26          fn.apply(context, args);
27      });
28  }
29  
30  /// @param {err} the error to be thrown
31  function reject(err) {
32      return Promise.reject(err);
33  }
34  
35  /// changes the promise implementation that bcrypt uses
36  /// @param {Promise} the implementation to use
37  function use(promise) {
38      Promise = promise;
39  }
40  
41  module.exports = {
42      promise,
43      reject,
44      use
45  }