TypeError: Cannot read property 'experience' of null (reactJS)

Question

I am student and learning ReactJS building a Web aplication and I am having problem with that error.

router.post('/experience', passport.authenticate('jwt', { session: false }), (req, res) => {
    const { errors, isValid } = validateExperienceInput(req.body);

//Check Validation
if (!isValid) {
    //Return any errors with 400 status
    return res.status(400).json(errors);
}

Profile.findOne({ user: req.user_id })
    .then(profile => {
        const newExp = {
            title: req.body.title,
            company: req.body.company,
        }
        //Add to experience array
        //There is the error generated
        profile.experience.unshift(newExp);
        profile.save().then(profile => res.json(profile));
    })
});

here is profile model where experience array is declared

const ProfileSchema = new Schema({
user: {
    type: Schema.Types.ObjectId,
    ref: 'users'
},
handle: {
    type: String,
    required: true,
    max: 40
},
experience: [
    {
        title: {
            type: String,
            required: true
        },
        company: {
            type: String,
            required: true
        },
    }
],
});

and thats the error I got

(node:14580) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'experience' of null
at C:\Users\HP 840 G3\Desktop\LinkedIn\routes\api\profile.js:180:21
at processTicksAndRejections (internal/process/task_queues.js:93:5)

I am using Visual Studio Code on Windows 10 Pro And testing app using Postman Web

Answer 1

profile.experience.unshift(newExp) this line causes the error (unless it is caused by the code you didn't post).

Possible cause is that your findOne did not actually "findOne" and returned undefined.

You could add an if

Profile.findOne({ user: req.user_id })
    .then(profile => {
        if (!profile) return
        const newExp = {
            title: req.body.title,
            company: req.body.company,
        }
        //Add to experience array
        //There is the error generated
        profile.experience.unshift(newExp);
        profile.save().then(profile => res.json(profile));
    })
});

Or any equivalent code.

Answer 2

Parameter profile is null. You need to pass the object to the resolve method in the Promise definition, findOne , (not shown above). Example:

 let findOne = new Promise(function(resolve, reject) { let resolveParam = { experience: [] }; setTimeout(() => resolve(resolveParam), 1000); }); findOne.then( profile => console.log(profile) );