如何将以下 nodejs 代码翻译成 ES6

Question

This is my first javascript project (also a first programming project after a decade) so go easy on me.

I am working on VueJS and using a module form nodejs. Now, I have a need to add some functionality to the nodejs module. I copied relevant files into my project. However, the files have syntax different from my code (it uses 'use strict; and require vs my code that uses export/import.

The code in question looks like this:

'use strict';

var SSH = module.exports;
var Enc = require('./encoding.js');

SSH.parse = function (opts) {
  var pub = opts.pub || opts;
  var ssh = SSH.parseBlock(pub);
  ssh = SSH.parseElements(ssh);
  //delete ssh.bytes;
  return SSH.parsePublicKey(ssh);
};

/*global Promise*/
SSH.fingerprint = function (opts) {
  var ssh;
  if (opts.bytes) {
    ssh = opts;
  } else {
    ssh = SSH.parseBlock(opts.pub);
  }
  // for browser compat
  return Promise.resolve().then(function () {
    return 'SHA256:' + require('crypto').createHash('sha256')
      .update(ssh.bytes).digest('base64').replace(/=+$/g, '');
  });
};
...
...

How can I translate this code into ES6 style. Where I can import this and make a call like SSH.fingerprint(publickey) .

Answer 1

how about this

exports.funcName = async (params) => {
  // your code
}

on other working file

const fileName = require('../path')
//call it
fileName.funcName()

Answer 2

Node modules use Commonjs Modules syntax.

In Node, we use require to import which is equivalent to import in es6. For export, we use modules.exports or exports which is equivalent to the export keyword in es6 Modules

import in NodeMoules

    var Enc = require('./encoding.js');

es6 Modules

    import * as Enc from './encoding.js';

export in NodeMoules

    const variable = 3;
    module.exports = {
    variable
    };

or

    exports.variable = 3;

es6 Modules

    export const variable = 3;

---

Edit to answer OP's comment

how do I translate var SSH = module.exports;

In Node Modules, whatever you defined on module.exports object it will be exported by the module. This means if you define anything on its reference it will also be exported because it is js reference it will point to the same object.

var SSH = module.exports;

this code, save a reference of module.exports in SSH variable. if you defined any key on the SSH variable it will be exported ie SSH.fingerprint.

So in order to export fingerprint in es6 Module you just need to do this

export const fingerprint = function (opts) {
  var ssh;
  if (opts.bytes) {
    ssh = opts;
  } else {
    ssh = SSH.parseBlock(opts.pub);
  }
  // for browser compat
  return Promise.resolve().then(function () {
    return 'SHA256:' + require('crypto').createHash('sha256')
      .update(ssh.bytes).digest('base64').replace(/=+$/g, '');
  });
};

FYI, exports keyword in node modules is also a reference to module.exports

---

Update for the second comment, Your final code will become:

'use strict';

import * as Enc './encoding.js';

export const parse = function (opts) {
  const pub = opts.pub || opts;
  const ssh = parseBlock(pub);
  ssh = parseElements(ssh);
  //delete ssh.bytes;
  return parsePublicKey(ssh);
};

/*global Promise*/
export const fingerprint = function (opts) {
  let ssh;
  if (opts.bytes) {
    ssh = opts;
  } else {
    ssh = parseBlock(opts.pub);
  }
  // for browser compat
  return Promise.resolve().then(function () {
    return 'SHA256:' + require('crypto').createHash('sha256')
      .update(ssh.bytes).digest('base64').replace(/=+$/g, '');
  });
};
...