TypeError[ERR_INVALID_ARG_TYPE]：&quot；原始&quot；参数必须是函数类型。接收的类型未定义 [英] TypeError [ERR_INVALID_ARG_TYPE]: The "original" argument must be of type Function. Received type undefined

问题描述

在以下代码中，我收到以下错误：

TypeError[ERR_INVALID_ARG_TYPE]："；Original"；参数必须是函数类型。接收的类型未定义

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')

它说问题在第31行：const dbGetAsync = util.promisify(db.get);

$ mocha src/tests/testStates.js
C:UsersCodyAppDataRoaming
pm
ode_modulesmocha
ode_modulesyargsyargs.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:UsersCodyProjectsgoggle-indexersrcstate.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:UsersCodyProjectsgoggle-indexersrc	ests	estStates.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:UsersCodyAppDataRoaming
pm
ode_modulesmochalibmocha.js:330:36
        at Array.forEach (<anonymous>)
        at Mocha.loadFiles (C:UsersCodyAppDataRoaming
pm
ode_modulesmochalibmocha.js:327:14)
        at Mocha.run (C:UsersCodyAppDataRoaming
pm
ode_modulesmochalibmocha.js:804:10)
        at Object.exports.singleRun (C:UsersCodyAppDataRoaming
pm
ode_modulesmochalibcli
un-helpers.js:207:16)
        at exports.runMocha (C:UsersCodyAppDataRoaming
pm
ode_modulesmochalibcli
un-helpers.js:300:13)
        at Object.exports.handler.argv [as handler] (C:UsersCodyAppDataRoaming
pm
ode_modulesmochalibcli
un.js:296:3)
        at Object.runCommand (C:UsersCodyAppDataRoaming
pm
ode_modulesmocha
ode_modulesyargslibcommand.js:242:26)
        at Object.parseArgs [as _parseArgs] (C:UsersCodyAppDataRoaming
pm
ode_modulesmocha
ode_modulesyargsyargs.js:1087:28)
        at Object.parse (C:UsersCodyAppDataRoaming
pm
ode_modulesmocha
ode_modulesyargsyargs.js:566:25)
        at Object.exports.main (C:UsersCodyAppDataRoaming
pm
ode_modulesmochalibclicli.js:63:6)
        at Object.<anonymous> (C:UsersCodyAppDataRoaming
pm
ode_modulesmochain\_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)

我在使用此Promisify库时遇到问题。

推荐答案

首先不需要在new Promise()内部使用return db;，因为它不需要来自回调函数的任何返回值。

由于getDB()是异步函数，需要与await关键字配合使用才能获取值，或者在.then的处理函数中可用。

您多次调用getDB()对我来说没有意义。

与其像exports.get = async function()这样直接将匿名函数分配给Exports对象键，然后从Exports对象中使用它在同一文件中使用，不如定义一个命名的GET函数，然后在导出的同时使用它。

更好的做法是将其直接分配给Exports对象键，然后从Exports对象中使用它以在同一文件中使用。

您正在new Promise()构造函数外部使用Reject和Resolve关键字，这是不可能的。

我已重写了您的代码，我不确定是否遗漏了什么，但请务必查看并通知您是否仍面临任何问题。

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;

这篇关于TypeError[ERR_INVALID_ARG_TYPE]：&quot；原始&quot；参数必须是函数类型。接收的类型未定义的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！