How can I loop through the keys of an object and set values equal to a destructured variable?

Question

I am trying to simplify and shorten my current code. My code is working fine. This is what I have:

app.patch('/listings/:id', (req, res) => {
    const { id } = req.params;
    console.log(req.body)
    const {
        leaser, propertyType, pricePerDay,
        currency, city, street, description
    } = req.body;
    const foundListing = listings.find(l => l.id === id);
    
    foundListing.leaser = leaser;
    foundListing.pricePerDay = pricePerDay;
    foundListing.propertyType = propertyType;
    foundListing.currency = currency;
    foundListing.city = city;
    foundListing.street = street;
    foundListing.description = description;

    res.redirect('/listings');
})

How can I make the repetitive last half of the code shorter? There is probably a way in which I can write only one line

Answer 1

You can use the spread operator .

app.patch('/listings/:id', (req, res) => {
    const { id } = req.params;
    console.log(req.body)
    const {
        leaser, propertyType, pricePerDay,
        currency, city, street, description
    } = req.body;
    
    const foundListing = {
        ...listings.find(l => l.id === id),
        ...req.body
    };

    res.redirect('/listings');
})

Answer 2

This isn't much shorter, but that's partly because we have it all in one place. If you had a util function to copy these properties, you cna just call it when needed.

Partially applying the functions is entirely down to personal preference ♂️

 const listings = [ { id: 1, name: "a" }, { id: 2, name: "b" }, ]; const copyProperties = ps => from => to => { ps.forEach(p => { to[p] = from[p]; }); } const applyRequestToListing = req => copyProperties([ "leaser", "pricePerDay", "propertyType", "currency", "city", "street", "description", ])(req); const handleRequest = (req) => { const foundListing = listings.find(l => { return l.id === req.params.id }); applyRequestToListing(req.body)(foundListing); }; handleRequest({ params: { id: 2, }, body: { leaser: "leaserIn", pricePerDay: "pricePerDayIn", propertyType: "propertyTypeIn", currency: "currencyIn", city: "cityIn", street: "streetIn", description: "descriptionIn", }, }); console.log(listings);

Answer 3

You can use Object.assign() in combination with the spread operator to add the additional properties to the found listing like this:

const foundListing = listings.find(l => l.id === id);
Object.assign(foundListing, ...req.body)

Or even shorter (as you probably don't need the foundListing variable later):

Object.assign(listings.find(l => l.id === id), ...req.body);

Suddenly your code becomes really short:

app.patch('/listings/:id', (req, res) => {
    Object.assign(listings.find(l => l.id === req.params.id), ...req.body);
    res.redirect('/listings');
})

Answer 4

If all the foundListing properties are going to be modified, then you could loop through the properties to make changes, like so:

app.patch('/listings/:id', (req, res) => {
    
    const { id } = req.params,
          foundListing = listings.find(l => l.id === id);

    for(const key in foundListing){ 
        foundListing[key] = req.body[key] 
    }

    res.redirect('/listings');
})

If you need to specify which properties are going to be modified then you can list them in an array and loop through them to make changes, like so:

app.patch('/listings/:id', (req, res) => {
    
    const { id } = req.params,
          foundListing = listings.find(l => l.id === id),
          keys = [
             'leaser', 
              'propertyType', 
              'pricePerDay',
              'currency', 
              'city', 
              'street', 
              'description'
          ];

    keys.forEach(key => { foundListing[key] = req.body[key] })
    res.redirect('/listings');
})

Answer 5

I would use the following approach.

app.patch('/listings/:id', (req, res) => {
   const { id } = req.params;
   const foundListing = listings.find(l => l.id === id);

   Object.keys(foundListing).forEach(key => {
     foundListing[key] = req.body[key]
   })

   res.redirect('/listings');
})