Promisifying Callbacks in Node.js

This question already has an answer here:

How do I convert an existing callback API to promises? 17 answers

---

The common pattern is:

<promisified> = function() {
    return new Promise(function(resolve, reject) {
       <callbackFunction>(function (err, result) {
           if (err)
               reject(err);
           else
               resolve(result);
       });
    });
}

For your specific example (to which you might want to add error handling):

readTemperature = function() {
    return new Promise(function(resolve) {
       htu21df.readTemperature(function (temp) {
          resolve(temp);
       });
    });
}

readTemperature().then(function(temp) {
    console.log('Temperature, C:', temp);
});

---

你需要为此使用蓝鸟。

var bluebird = require('bluebird');
var i2c_htu21d = require('htu21d-i2c');
var htu21df = new i2c_htu21d();
var readTemperature = bluebird.promisify(htu21df.readTemperature);


readTemperature().then((temp) => {console.log('Temperature, C:', temp);});

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