Question 52124 in Javascript Question posted in
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How to update reference models in mongoose by updating one model? – Javascript

I have two models Skill and Course. Whenever I update any existing skills name, I want it to update the skill name inside the course object, that already has these skills.

How can I automatically update the name of skills in course.skills when I update any skill?

Course models :

    const courseSchema = new mongoose.Schema(
        {
            name: {
                type: String,
                required: true,
                trim: true,
            },
            description: {
                type: String,
            },
            
            skills: [
                {
                    name: { type: String },
                    id: { type: mongoose.Schema.Types.ObjectId, ref: 'Skill' },
                },
            ],
        }
    );

Skill Model:

    const Course = require('./course.model');
    
    const skillSchema = new mongoose.Schema(
        {
            name: {
                type: String,
                required: true,
                trim: true,
            },
            description: {
                type: String,
            },
            points: {
                type: Number,
            },
        },
        {
            timestamps: true,
        }
    );

this is the function for updating the skills:

    module.exports.updateSkillById = async (req, res) => {
        const updates = Object.keys(req.body);
        const allowedUpdates = ['name', 'description', 'points'];
        const isValidOperation = updates.every((update) =>
            allowedUpdates.includes(update)
        );
        if (!isValidOperation) {
            return res.status(400).send({ error: 'Invalid updates!' });
        }
        try {
            const skill = await Skill.findOneAndUpdate(req.params.id, req.body, {
                new: true,
                runValidators: true,
            });
            if (!skill) {
                return res.status(404).send();
            }
          
            res.send(skill);
        } catch (err) {
            res.status(400).send(err);
        }
    };
Tags:

2

Answers


  1. Chosen as BEST ANSWER
    0

    I am solving this problem by using save() method. Using save() method instead of findByIdAndUpdate() will return the updated object in pre hook.

    the update function is like that :

    
     const skill = await Skill.findById(req.params.id);
            if (!skill) {
                return res.status(404).send();
            }
            updates.forEach((update) => (skill[update] = req.body[update]));
            await skill.save();

    The pre-hook is :

    
skillSchema.pre('save', async function (next) {
    const skill = this;

    const courses = await Course.find({ 'skills.id': skill._id });
   
    await updateModel(courses, skill, 'skills');

   if (courses.length > 0) {
    await Promise.all(
        courses.map((course) => {
            const skillIndex = course.skills.findIndex((sk) =>
                sk.id.equals(skill._id)
            );
            course.skills[skillIndex].name = skill.name;
            return course.save();
        })
    );
}
    next();
});

  2. 0

    One way to achieve that is to use Mongoose middleware functions. You can use a pre(‘findOneAndUpdate) hook in the skill model.

    This will trigger before updating the skill object.

    Inside the hook you can update your courses manually with a transaction.

    skillSchema.pre('findOneAndUpdate', async function(next) {
    const skill = this.getUpdate();
    const courses = await Course.find({ 'skills.id': skill._id });

    if (courses.length > 0) {
        try {
            const session = await mongoose.startSession();
            session.startTransaction();

            for (let i = 0; i < courses.length; i++) {
                const course = courses[i];
                const skillIndex = course.skills.findIndex(s => s.id.equals(skill._id));

                if (skillIndex >= 0) {
                    course.skills[skillIndex].name = skill.name;
                    await course.save({ session });
                }
            }

            await session.commitTransaction();
        } catch (err) {
            await session.abortTransaction();
            throw err;
        }
    }

    next();
});
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