TypeError [ERR_INVALID_ARG_TYPE]：“原始”参数的类型必须为 Function。接收到的类型未定义

Question

In the following code, I get this error:

TypeError [ERR_INVALID_ARG_TYPE]: The "original" argument must be of type Function. Received type undefined

const sqlite3 = require('sqlite3').verbose();
const util = require('util');

async function getDB() {
  return new Promise(function(resolve, reject) {
    let db = new sqlite3.Database('./project.db', (err) => {
      if (err) {
        console.error(err.message);
        reject(err)
      } else {
        console.log('Connected to the project database.');
        resolve(db)
      }
    });
    return db
  });
}


try {
  // run these statements once to set up the db
  let db = getDB();
  db.run(`CREATE TABLE services(id INTEGER PRIMARY KEY, service text, date text)`);
  db.run(`INSERT INTO services(id, service, date) VALUES (1, 'blah', '01-23-1987')`)
} catch(err) {
  console.log(err)
}


const db = getDB();
const dbGetAsync = util.promisify(db.get);

exports.get = async function(service) {

  let sql = `SELECT Id id,
    Service service,
    Date date
    FROM services
    WHERE service  = ?`;

  const row = await dbGetAsync(sql, [service], (err, row) => {
    if (err) {
      console.error(err.message);
      reject(err)
    }
    let this_row = {'row': row.id, 'service': row.service};
    this_row ? console.log(row.id, row.service, row.date) : console.log(`No service found with the name ${service}`);
    resolve(this_row)
  });

  return row;
}

let row = exports.get('blah')

It says the problem is in line 31: const dbGetAsync = util.promisify(db.get);

$ mocha src/tests/testStates.js
C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\node_modules\yargs\yargs.js:1163
      else throw err
           ^

    TypeError [ERR_INVALID_ARG_TYPE]: The "original" argument must be of type Function. Received type undefined
        at Object.promisify (internal/util.js:256:11)
        at Object.<anonymous> (C:\Users\Cody\Projects\goggle-indexer\src\state.js:32:25)
        at Module._compile (internal/modules/cjs/loader.js:701:30)
        at Object.Module._extensions..js (internal/modules/cjs/loader.js:712:10)
        at Module.load (internal/modules/cjs/loader.js:600:32)
        at tryModuleLoad (internal/modules/cjs/loader.js:539:12)
        at Function.Module._load (internal/modules/cjs/loader.js:531:3)
        at Module.require (internal/modules/cjs/loader.js:637:17)
        at require (internal/modules/cjs/helpers.js:22:18)
        at Object.<anonymous> (C:\Users\Cody\Projects\goggle-indexer\src\tests\testStates.js:7:15)
        at Module._compile (internal/modules/cjs/loader.js:701:30)
        at Object.Module._extensions..js (internal/modules/cjs/loader.js:712:10)
        at Module.load (internal/modules/cjs/loader.js:600:32)
        at tryModuleLoad (internal/modules/cjs/loader.js:539:12)
        at Function.Module._load (internal/modules/cjs/loader.js:531:3)
        at Module.require (internal/modules/cjs/loader.js:637:17)
        at require (internal/modules/cjs/helpers.js:22:18)
        at C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\lib\mocha.js:330:36
        at Array.forEach (<anonymous>)
        at Mocha.loadFiles (C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\lib\mocha.js:327:14)
        at Mocha.run (C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\lib\mocha.js:804:10)
        at Object.exports.singleRun (C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\lib\cli\run-helpers.js:207:16)
        at exports.runMocha (C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\lib\cli\run-helpers.js:300:13)
        at Object.exports.handler.argv [as handler] (C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\lib\cli\run.js:296:3)
        at Object.runCommand (C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\node_modules\yargs\lib\command.js:242:26)
        at Object.parseArgs [as _parseArgs] (C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\node_modules\yargs\yargs.js:1087:28)
        at Object.parse (C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\node_modules\yargs\yargs.js:566:25)
        at Object.exports.main (C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\lib\cli\cli.js:63:6)
        at Object.<anonymous> (C:\Users\Cody\AppData\Roaming\npm\node_modules\mocha\bin\_mocha:10:23)
        at Module._compile (internal/modules/cjs/loader.js:701:30)
        at Object.Module._extensions..js (internal/modules/cjs/loader.js:712:10)
        at Module.load (internal/modules/cjs/loader.js:600:32)
        at tryModuleLoad (internal/modules/cjs/loader.js:539:12)
        at Function.Module._load (internal/modules/cjs/loader.js:531:3)
        at Function.Module.runMain (internal/modules/cjs/loader.js:754:12)
        at startup (internal/bootstrap/node.js:283:19)
        at bootstrapNodeJSCore (internal/bootstrap/node.js:622:3)

I'm having problems using this promisify library.

Answer 1

First of all no need to use return db; inside new Promise() because it is not expecting any return value from the callback function.

Since getDB() is an asynchronous function, it needs to be used with await keyword to get the value or will be available in handler function of .then .

It doesn't make sense to me that you are calling getDB() multiple times.

It is better to read if instead of directly assigning an anonymous function to exports object key like this exports.get = async function() and then use it from exports object for use in same file, it would be better to define a named get function and then use it as well as export it.

You are using reject and resolve keywords outside new promise() constructor which is not possible.

I have rewritten your code, I am not sure if I have missed anything, but do take a look and please inform if you are still facing any issues.

const sqlite3 = require("sqlite3").verbose();
const util = require("util");

async function getDB() {
  return new Promise(function(resolve, reject) {
    let db = new sqlite3.Database("./project.db", err => {
      if (err) {
        console.error(err.message);
        reject(err);
      } else {
        console.log("Connected to the project database.");
        resolve(db);
      }
    });
  });
}

try {
  // run these statements once to set up the db
  let db = await getDB();
  db.run(
    `CREATE TABLE services(id INTEGER PRIMARY KEY, service text, date text)`
  );
  db.run(
    `INSERT INTO services(id, service, date) VALUES (1, 'blah', '01-23-1987')`
  );
} catch (err) {
  console.log(err);
}

const db = await getDB();
const dbGetAsync = util.promisify(db.get);

async function get(service) {
  let sql = `SELECT Id id, Service service, Date date FROM services WHERE service  = ?`;

  try {
    const row = await dbGetAsync(sql, [service]);
    let this_row = { row: row.id, service: row.service };
    this_row
      ? console.log(row.id, row.service, row.date)
      : console.log(`No service found with the name ${service}`);
    return row;
  } catch (err) {
    console.error(err.message);
  }
}

let row = await get("blah");

exports.get = get;

Answer 2

我收到此错误是因为我使用的是旧 Node 版本 (8.17.0)，将 Node 更新到较新版本 (12.14.0) 修复了此错误。

Answer 3

getDB is an async function returning a Promise, so you have to await for the promise to resolve or chain a then to use its returned value:

// you have to put it inside an async function
const db = await getDB();
const dbGetAsync = util.promisify(db.get);

getDB().then(function(db){
  return util.promisify(db.get);
}).then(function(getFunction){
  // use get
})

Answer 4

Use await before getDB() as it is return promise, so that is why you are getting error. see the correction below:

const db = await getDB();
const dbGetAsync = util.promisify(db.get);

Also you have to wrap await inside async function other it won't work like this:

(async function(){
  let bar = await foo();
})()

Answer 5

ERR_INVALID_ARG_TYPE is internal Node.js error. It means that your code may invoke build-int function with wrong arguments.

I've faced same error (ERR_INVALID_ARG_TYPE) but with much simpler code and in different circumstances.

const readFileAsync = util.promisify(fs.readFile);
const readDirAsync = util.promisify(fs.readdir);

Reason was that fs.readFile and fs.readdir were both undefined. If you call util.promisify with undefined then Node.js produce a error ERR_INVALID_ARG_TYPE.

In my case reason was that unit test was mocking build-in fs module and some of dependencies were initialized with 2 lines of code above.