---
# System prepended metadata

title: MERN Common Errors
tags: [Debugging, MERN, JavaScript]

---

###### tags: `MERN`, `Debugging`, `JavaScript`
# MERN Common Errors

**Map is Not a Function**

![](https://i.imgur.com/lIqrZtw.png)


.map function is **only** for arrays `[]` and this error occurs when the data you are iterating through is not a an array but another data structure like an object `{}`. 

To fix this, we need to change our data type to an array `[]`. First step is to identify our **state** that holds the data. 

<img src="https://i.imgur.com/wZYaDUZ.png" />


<img src="https://i.imgur.com/7iYeCd6.png" />


Here is an example of data pulling from our API:

<img src="https://i.imgur.com/wmuBVQh.png" width="150px"/>


Our error is in our setter:

<img src="https://i.imgur.com/k8RoDSj.png" />


Notice the DATA CONTAINS AN OBJECT CALLED DATA, AND AN ARRAY CALLED DATA INSIDE THE DATA OBJECT.

HERE IS THE FIX:

![](https://i.imgur.com/tpr77Tj.png)


WE HAVE NOTATED CORRECTLY INTO THE BUCKET OF DATA, AND ARE NOW ABLE TO ITERATE OVER THE DATA BECAUSE IT IS NOW AN ARRAY


**this section up above is not finished** 

---

ERROR -> "cannot find module..."

![](https://i.imgur.com/Y5MQ7JM.png)

WHY?
Pathing Issues, Please check your folder structure which should look something like this below:


![](https://i.imgur.com/gXDZBa7.png)


![](https://i.imgur.com/Av6AaXH.png)


SOLUTION -> change your path url of the file you are trying to import by using dots and slashes, like this:

```
./config/mongoose.config

```



---




