const form = await Form.findOne({ _id: res._id }).populate({
path: "activity.viewedBy",
model: User,
});
const a = await form.activity.map((a) => a.viewedBy);
console.log(a.map((e) => e.email));
"Cannot read property 'email' of undefined"
Why?
a is an array, full of objects, like this:
[
{
id: 123,
email: example@email.com
},
{
id: 456,
email: nice@email.com
}
]
Edit, sharing the whole async function:
const viewForm = async (req, res) => {
const form = await Form.findOne({ _id: res._id }).populate({
path: "activity.viewedBy",
model: User,
});
const a = await form.activity.map((a) => a.viewedBy);
console.log(a.map((e) => e.email));
await Form.updateOne(
{ _id: res._id },
{
$push: {
activity: {
viewedBy: res.user,
date: new Date(),
},
},
}
);
return {
statusCode: 200,
body: JSON.stringify(`Form viewed.`),
};
};
Edit2:
There was an undefined in the array, among the objects, I didn't notice that... That's why I was getting the undefined.
a probably has a different structure than you think (try console.log(a)), just proving:
const data = [
{
id: 123,
email: "example@email.com"
},
{
id: 456,
email: "nice@email.com"
}
];
const result = data.map((a) => a.email);
console.log(result);Also, giving your variables meaningful names can help to prevent mistakes.
await form.activity.map((a) => a.viewedBy);
will return an array of viewedBy values. So the array a doesn't contain the full objects. Instead, it contains an array of viewedBy elements.
Also, please take a look at the functionality of the map() function.