util.promisify.custom

• <symbol> 可用于声明自定义的 promise 化的函数变体，参阅自定义的 promise 化函数。

除了可以通过 util.promisify.custom 访问之外，此符号是全局地注册，可以在任何环境中作为 Symbol.for('nodejs.util.promisify.custom') 访问。

例如，对于接受 (foo, onSuccessCallback, onErrorCallback) 的函数：

const kCustomPromisifiedSymbol = Symbol.for('nodejs.util.promisify.custom');

doSomething[kCustomPromisifiedSymbol] = (foo) => {
  return new Promise((resolve, reject) => {
    doSomething(foo, resolve, reject);
  });
};

• <symbol> that can be used to declare custom promisified variants of functions, see Custom promisified functions.

In addition to being accessible through util.promisify.custom, this symbol is registered globally and can be accessed in any environment as Symbol.for('nodejs.util.promisify.custom').

For example, with a function that takes in (foo, onSuccessCallback, onErrorCallback):

const kCustomPromisifiedSymbol = Symbol.for('nodejs.util.promisify.custom');

doSomething[kCustomPromisifiedSymbol] = (foo) => {
  return new Promise((resolve, reject) => {
    doSomething(foo, resolve, reject);
  });
};