CODEWITHSUNDEEP
javascript
Chap
Chap

Reputation: 3553

Search an array for matching attribute

I have an array, I need to return a restaurant's name, but I only know the value of its "food" attribute (not it's index number).

For example, how could I return "KFC" if I only knew "chicken"?

restaurants = 
  [
    {"restaurant" : { "name" : "McDonald's", "food" : "burger" }},
    {"restaurant" : { "name" : "KFC",        "food" : "chicken" }},
    {"restaurant" : { "name" : "Pizza Hut",  "food" : "pizza" }}
  ];

Upvotes: 87

Views: 209621

Answers (8)

chenkehxx
chenkehxx

Reputation: 1625

you can also use the Array.find feature of es6. the doc is here

return restaurants.find(item => {
   return item.restaurant.food == 'chicken'
})

Upvotes: 83

Paulo Belo
Paulo Belo

Reputation: 4437

let restaurant = restaurants.find(element => element.restaurant.food == "chicken");

The find() method returns the value of the first element in the provided array that satisfies the provided testing function.

as you can see in MDN Web Docs

Upvotes: 9

Ben
Ben

Reputation: 57209

for (x in restaurants) {
    if (restaurants[x].restaurant.food == 'chicken') {
        return restaurants[x].restaurant.name;
    }
}

Upvotes: 9

Hakan Bilgin
Hakan Bilgin

Reputation: 1122

@Chap - you can use this javascript lib, DefiantJS (http://defiantjs.com), with which you can filter matches using XPath on JSON structures. To put it in JS code:

var data = [
   { "restaurant": { "name": "McDonald's", "food": "burger" } },
   { "restaurant": { "name": "KFC",        "food": "chicken" } },
   { "restaurant": { "name": "Pizza Hut",  "food": "pizza" } }
].
res = JSON.search( data, '//*[food="pizza"]' );

console.log( res[0].name );
// Pizza Hut

DefiantJS extends the global object with the method "search" and returns an array with matches (empty array if no matches were found). You can try out the lib and XPath queries using the XPath Evaluator here:

http://www.defiantjs.com/#xpath_evaluator

Upvotes: 1

He Nrik
He Nrik

Reputation: 1700

In this case i would use the ECMAscript 5 Array.filter. The following solution requires array.filter() that doesn't exist in all versions of IE.

Shims can be found here: MDN Array.filter or ES5-shim

var result = restaurants.filter(function (chain) {
    return chain.restaurant.food === "chicken";
})[0].restaurant.name;

Upvotes: 53

Jhankar Mahbub
Jhankar Mahbub

Reputation: 9848

you can use ES5 some. Its pretty first by using callback

function findRestaurent(foodType) {
    var restaurant;
    restaurants.some(function (r) {
        if (r.food === id) {
            restaurant = r;
            return true;
        }
   });
  return restaurant;
}

Upvotes: 1

laVie
laVie

Reputation: 69

Must be too late now, but the right version would be: 

for(var i = 0; i < restaurants.restaurant.length; i++)
{
  if(restaurants.restaurant[i].food == 'chicken')
  {
    return restaurants.restaurant[i].name;
  }
}

Upvotes: 3

Matthew Flaschen
Matthew Flaschen

Reputation: 284786

for(var i = 0; i < restaurants.length; i++)
{
  if(restaurants[i].restaurant.food == 'chicken')
  {
    return restaurants[i].restaurant.name;
  }
}

Upvotes: 82

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