How to map Element value on Multiple array

Question

These are the Few arrays name:

var Transport = ['Bus', 'Car', 'Truck', 'Train'];
var Fruits = ['Apple', 'Banana', 'Grape'];
var Animals = ['Dog', 'Cat', 'Horse', 'Sheep'];

And I have a result set like this:

var x = [
            {'name': 'Bus'},
            {'name': 'Banana'},
            {'name': 'Car'},
            {'name': 'Dog'},
            {'name': 'Truck'},
            {'name': 'Cat'}
          ];

Now what I want Some logic which return That which element is lies on which category. Example is like this

//what I want: 
var newresultTransport = ['Bus', 'Car', 'Truck'];
var newresultAnimal = ['Dog', 'Cat'];
var newresultFruits = ['Banana'];

Any Help is apprecited

Nina Scholz · Accepted Answer · 2017-12-22 13:19:03Z

3

You could use an object for the groups, for the single values and for the result. Then generate a hash table to get the group for every name and use it for creating a group in the result set and push the name to this group.

var groups = { transport: ['Bus', 'Car', 'Truck', 'Train'], fruits: ['Apple', 'Banana', 'Grape'], animals: ['Dog', 'Cat', 'Horse', 'Sheep'] },
    array = [{ name: 'Bus' }, { name: 'Banana' }, { name: 'Car' }, { name: 'Dog' }, { name: 'Truck' }, { name: 'Cat' }],
    hash = {},
    grouped = {};

Object.keys(groups).forEach(function (k) {
    groups[k].forEach(function (a) {
        hash[a] = k;
    });
});

array.forEach(function (o) {
    var k = hash[o.name];
    grouped[k] = grouped[k] || [];
    grouped[k].push(o.name);
});

console.log(grouped);

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answered Dec 22, 2017 at 13:19

Nina Scholz

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1 Comment

Iron_Man Over a year ago

Thank you so much Nina Scholz.

gurvinder372 · Accepted Answer · 2017-12-22 13:14:31Z

First transform x to an array of strings using map

x = x.map( s => s.name ) ;

Now use filter

newresultTransport = Transport.filter( s => x.indexOf( s ) != -1 );

Similarly for Fruits and animals

newresultAnimal = Fruits.filter( s => x.indexOf( s ) != -1 );
newresultFruits = Animals.filter( s => x.indexOf( s ) != -1 );

Demo

var Transport = ['Bus', 'Car', 'Truck', 'Train'];
var Fruits = ['Apple', 'Banana', 'Grape'];
var Animals = ['Dog', 'Cat', 'Horse', 'Sheep'];
var x = [
  {'name': 'Bus'},
  {'name': 'Banana'},
  {'name': 'Car'},
  {'name': 'Dog'},
  {'name': 'Truck'},
  {'name': 'Cat'}
];
x = x.map( s => s.name ) ;
var newresultTransport = Transport.filter( s => x.indexOf( s ) != -1 );
var newresultAnimal = Fruits.filter( s => x.indexOf( s ) != -1 );
var newresultFruits = Animals.filter( s => x.indexOf( s ) != -1 );
   
console.log( newresultTransport , newresultAnimal , newresultFruits  );

Stephen Reynolds · Accepted Answer · 2017-12-22 13:41:35Z

When creating var "x" in your question:

var x = [
{'name': 'Bus'},
{'name': 'Banana'},
{'name': 'Car'},
{'name': 'Dog'},
{'name': 'Truck'},
{'name': 'Cat'}
]

1) You left out the categories. You can can revise "x" to include a "category" property for each object.

var x = [
{'name': 'Bus', 'category':'transport'},
{'name': 'Banana', 'category':'fruit'},
{'name': 'Car', 'category':'transport'},
{'name': 'Dog', 'category':'animal'},
{'name': 'Truck', 'category':'transport'},
{'name': 'Cat', 'category':'animal'}
]

2) You can then use filter to filter the array down to a category desired. Example:

var x = [
{'name': 'Bus', 'category':'transport'},
{'name': 'Banana', 'category':'fruit'},
{'name': 'Car', 'category':'transport'},
{'name': 'Dog', 'category':'animal'},
{'name': 'Truck', 'category':'transport'},
{'name': 'Cat', 'category':'animal'}
]

const justTransport = x.filter(function(el){
    return el.category === "transport"
});

console.log(justTransport);

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