Records Set

Class for storing a set of records with unique property.

Installation

To install this module use npm or yarn:

npm install @creanet/records-set

yarn add @creanet/records-set

After the module is installed, require it anywhere in the code:

const RecordsSet = require('@creanet/records-set');

Creating new instance

To create a new instance of Records Set, constructor should be called with two parameters:

const RecordsSet = require('@creanet/records-set');

const uniqueProp = 'id';
const iterable = [
  {
    id: '1',
    foo: 'obj1'
  },
  {
    id: '2',
    foo: 'obj2'
  },
  {
    id: '2',
    foo: 'obj3'
  }
];

const set = new RecordsSet(uniqueProp, iterable);

console.log(set.values()); // [ { id: '1', foo: 'obj1' }, { id: '2', foo: 'obj2' } ]

Properties

size

Returns the number of the records in RecordsSet:

console.log(set.size); // 2
console.log(set.size === set.values().length); // true

Methods

values()

Returns an array with all records (values):

console.log(set.values()); // [ { id: '1', foo: 'obj1' }, { id: '2', foo: 'obj2' } ]

has(record)

Determines whether set contains such record by looking for unique property. All other properties will be ignored:

console.log(set.has({ id: '2', foo: 'obj2' })); // true
console.log(set.has({ id: '2', foo: 'obj3' })); // true
console.log(set.has({ id: '3', foo: 'obj4' })); // false

add(values)

Used to add one or more records. Records with already registered unique prop will be ignored:

set.add({ id: '2', foo: 'obj5' });
console.log(set.size); // 2

set.add({ id: '3', foo: 'obj6' });
console.log(set.size); // 3

delete(values)

Used to delete one or more records. Delete can either be passed a record with the unique property:

set.delete({ id: '2', foo: 'obj7' });
console.log(set.values()); // [ { id: '1', foo: 'obj1' }, { id: '3', foo: 'obj6' } ]

Or a simple value:

set.delete('1');
console.log(set.values()); // [ { id: '3', foo: 'obj6' } ]

clear()

Removes all records:

set.clear();
console.log(set.values()); // []

Iteration methods

Records set can be iterated using these methods:

set.forEach(callback, thisArg);
set.map(callback, thisArg);
set.filter(callback, thisArg);

Methods map and filter return a new instance of RecordsSet, forEach returns the original RecordsSet. Alternatively it is possible to use any array iteration method by calling it on the values of the set:

set.values()[iterationMethod];

Some array iteration methods return an array. To turn the result into set, simply call:

set = new Set(set.uniqueProp, set.values().map(callback));