TypeError：util.promisify不是函数吗？

Question

I'm trying to promisify zlib.gunzip in my react application:

const zlib = require('zlib')
const util = require('util')

const gunzipPromisified = util.promisify(zlib.gunzip)

But I get this error:

TypeError: util.promisify is not a function

That works fine if I put it in a standalone script file and run it through node .

If I try:

import zlib from 'zlib'
import util from 'util'

const gunzipPromisified = util.promisify(zlib.gunzip)

I get something even fancier:

TypeError: __WEBPACK_IMPORTED_MODULE_8_util___default.a.promisify is not a function

What am I missing?

[Edit] The node.js version installed on my laptop is 8.9.1.

[Edit] As somebody commented, the node.js installed in my local development environment has nothing to do with what the app code has access to in the browser. So now my question is, how do I determine what API I have access to in the browser?

Answer 1

I had the same problem, it got fixed by updating Node to a version higher than Node 7.

n latest

In my case Node 9.2.0 as this was added later.

Answer 2

I had the same problem in Ionic. The util promisify didn't work for me either, and generated the same error as the one for OP. I ended up using this simple solution copied below:

const promisify = (fn) => {
 return (...args) => {
    return new Promise((resolve, reject)=>{
      fn(...args, function(err, res){
        if(err){
          return reject(err);
        }
        return resolve(res);
      })
    })
  }
}

And then:

const requestPromisified = promisify(request)

Answer 3

当然，当我切换到bluebird的Promise时，一切正常。