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PouchDB – Call get() in function ( TypeError: cb is not a function )

I am trying to make a simple login system using PouchDB, but I have a problem when I want to call db.get() in my function logIn()

  var submit = $("input[name='submit']");
  function logIn() {
    var username = $("input[name='username']").value;
    var password = $("input[name='password']").value;

    db.get(table.users, (err, info) => { // <-- Pouch db get() function to get data
      if (!err) {
        var data = ("db value", info);
        for (i = 0; i < 2; i++) {
          if (username == data[i].name && password == data[i].pass) {
            console.log(username + " is logged in!");
            return;
          }
        }
        console.log("Incorrect data!");
      } else {
        console.log("err field", err);
      }
    });
    db.get(); // <-- Here I call get() function
  }
  
  submit.click(() => {
    logIn(); // <-- On click call login() function
  });

In the console I get

Uncaught (in promise) TypeError: cb is not a function

is there a better option for this?

Answer

The error

Uncaught (in promise) TypeError: cb is not a function

Is thrown in db.get() because the code is calling the get method without a callback parameter (no parameters in fact).

The logIn method is calling db.get twice, first here

db.get(table.users, (err, info) => { // <-- Pouch db get() function to get data
 ...
});

and then here

db.get(); // <-- Here I call get() function

The second call fails immediately. It appears the thinking is db.get(table.users,(err,info) => is defining db.get but it’s not, it’s an actual call.

The snippet below demonstrates db.get with callback. I left an async/await example in there. See the pouchDB documentation for get

const g_result = 'result';
const gel = id => document.getElementById(id);
let db;

function logIn(userName, password) {
  const view = gel(g_result);
  // get the Users doc using get
  db.get("Users", (err, doc) => {
    if (err) {
      view.innerText = JSON.stringify(err, undefined, 3);
    } else {
      let info = doc.data.find(e => e.name === userName && e.pass === password);
      if (info) {
        view.innerText = `👍 Welcome ${userName}!`;
      } else {
        view.innerText = `👎 Log in failed, try again.`;
      }
    }
  });
}

async function logInAwait(userName, password) {
  const view = gel(g_result);
  
  let text = "";
  try {
    let doc = await db.get("Users");
    let info = doc.data.find(e => e.name === userName && e.pass === password);
    if (info) {
      text = `👍 Welcome ${userName}!`;
    } else {
      text = `👎 Log in failed, try again.`;
    }
  } catch (err) {
    text = JSON.stringify(err, undefined, 3);
  } finally {
    view.innerText = text;
  }

}

// canned documents
function getDocsToInstall() {
  return [{
    _id: "Users",
    data: [{
        name: "Jerry",
        pass: "Garcia"
      },
      {
        name: "Bob",
        pass: "Weir"
      },
      {
        name: "Wavy",
        pass: "Gravy"
      },
    ]
  }];
}

// init example db instance
async function initDb() {
  db = new PouchDB('test', {
    adapter: 'memory'
  });

  await db.bulkDocs(getDocsToInstall());
};

(async() => {
  await initDb();
  gel("form").style = "";
})();
<script src="https://github.com/pouchdb/pouchdb/releases/download/7.1.1/pouchdb-7.1.1.min.js"></script>
<script src="https://github.com/pouchdb/pouchdb/releases/download/7.1.1/pouchdb.memory.min.js"></script>
<pre id="form" style="display: none">
<label for="user">User Name</label>
<input id="user" /> 
<label for="pass">Password</label>
<input id="pass" /> <br/>
<button onclick="logIn(gel('user').value,gel('pass').value)">Log In (callback)</button>&nbsp;<button onclick="logInAwait(gel('user').value,gel('pass').value)">Log In (async)</button>
</pre>
<hr/>
<pre id='result'></pre>