This is JavaScript Array extended. It can throw event change. You can use it for something like light version of Backbone Collection.

new Arr([item1, item2, ..., itemN])

Initialize new array with items: item1, item2, ..., itemN.

Properties

events

List of Attached Events.

var fruits = new Arr('apple', 'orange', 'pineapple');

fruits.on('change', function(event) {
  console.log('fruits list is changed.');
});

// fruits.events
// [{
//  "name": "change",
//  "handler": function() { ... }
// }]

fruits.push('mango');
// fruits list is changed.
// fruits
// ['apple', 'orange', 'pineapple', 'mango']

length

Standard property [length](Standart accessor methods supported).

Accessor methods

get(index [, defaultValue])

Example:

var fruits = new Arr('apple', 'orange', 'pineapple');

fruits.get(0);
// apple

fruits.get(10, 'lime'); // trying to get undefined element - return defaultValue
// lime

fruits.get(20); // trying to get undefined element
// undefined

Standard accessor methods are supported

• concat() Returns a new array comprised of this array joined with other array(s) and/or value(s).
• join() Joins all elements of an array into a string.
• slice() Extracts a section of an array and returns a new array.
• toString() Returns a string representing the array and its elements. Overrides the Object.prototype.toString() method.
• toLocaleString() Returns a localized string representing the array and its elements. Overrides the Object.prototype.toLocaleString() method.
• indexOf() Returns the first (least) index of an element within the array equal to the specified value, or -1 if none is found.
• lastIndexOf() Returns the last (greatest) index of an element within the array equal to the specified value, or -1 if none is found.

and other methods.

Mutator methods

Notice: Traditional mutator arr[index] = value do not trigger event change. Use method set(index, value) instead arr[index] = value.

set(index, value)

Set value by index. Will be triggered event change.

Example:

var fruits = new Arr('apple', 'orange', 'pineapple');

fruits.set(0, 'banana');
// ['banana', 'orange', 'pineapple']

fruits.set(1, 'lime');
// ['banana', 'lime', 'pineapple']

fruits.set(3, 'nut');
// ['banana', 'lime', 'pineapple', 'nut']

insert([item1, item2, ..., itemN])

Insert array of items. Will be triggered event change.

Example:

var fruits = new Arr();

fruits.insert('apple', 'orange', 'pineapple');
// ['apple', 'orange', 'pineapple']

update(handler)

Update item if handler return true. Will be triggered event change if one or more items updated.

handler can recive data:

• value (mixed) current value
• index (number) current index

Example:

var fruits = new Arr('apple', 'orange', 'pineapple');

fruits.update(function(value, index) {
  if (index === 2) {
    return 'lime';  // "return" not undefined value for update item
  }
});
// ['apple', 'orange', 'lime']

fruits.update(function(value, index) {
  return index;
});
// [0, 1, 2]

remove(handler)

Remove item if handler return true. Will be triggered event change if one or more items removed.

Example:

var fruits = new Arr('apple', 'orange', 'pineapple');

fruits.remove(function(value, index) {
  if (value.indexOf('apple') !== -1) {
    return true;
  }
});
// ['orange']

Standard mutator methods are supported

Each mutator method throw event change. How? You can read in section Events.

• pop() Removes the last element from an array and returns that element.
• push() Adds one or more elements to the end of an array and returns the new length of the array.
• reverse() Reverses the order of the elements of an array — the first becomes the last, and the last becomes the first.
• shift() Removes the first element from an array and returns that element.
• sort() Sorts the elements of an array in place and returns the array.
• splice() Adds and/or removes elements from an array.
• unshift() Adds one or more elements to the front of an array and returns the new length of the array.

and other methods.

Sometimes you need to push array of items to Arr. You can push array of items in this way (note: now you can use method insert()):

var fruits = new Arr;

fruits.push.apply(fruits, ['apple', 'orange', 'pineapple']);
// fruits
// ['apple', 'orange', 'pineapple']

For remove item(s) from Arr you can use traditional method splice() (note: now you can use method remove()).

var fruits = new Arr('apple', 'orange', 'pineapple');

fruits.splice(0, 1); // remove first item
// fruits
// ['orange', 'pineapple']

Iteration methods

• forEach() Calls a function for each element in the array.
• every() Returns true if every element in this array satisfies the provided testing function.
• some() Returns true if at least one element in this array satisfies the provided testing function.
• filter() Creates a new array with all of the elements of this array for which the provided filtering function returns true.
• map() Creates a new array with the results of calling a provided function on every element in this array.
• reduce() Apply a function against an accumulator and each value of the array (from left-to-right) as to reduce it to a single value.
• reduceRight() Apply a function against an accumulator and each value of the array (from right-to-left) as to reduce it to a single value.

and other methods.

You can use method filter() for searching items by conditions.

Example:

var fruits = new Arr('apple', 'orange', 'pineapple');

var fruitsWithWordApple = fruits.filter(function(value, index) {
  if (value.indexOf('apple') !== -1) {
    return true;
  } else {
    return false;
  }
});
// fruitsWithWordApple
// ['apple', 'pineapple']

Events

Instance of Arr throw only one event change.

How to use events? You can use array events like events in Backbone Collection.

var fruits = new Arr('apple', 'orange', 'pineapple');

fruits.on('change', function(event) {
  // event
  // {
  //   "type": "insert",
  //   "items": ['mongo']
  // }
  
  console.log('fruits list is changed.');
});

// fruits.events
// [{
//  "name": "change",
//  "handler": function() { ... }
// }]

fruits.push('mango');
// fruits list is changed.
// fruits
// ['apple', 'orange', 'pineapple', 'mango']

Events Handling and Triggering

Notice: Traditional mutator arr[index] = value do not trigger event change. Use method set(index, value) instead arr[index] = value.

on(eventName, handler)

Attach event handler.

handler can recive event that have data:

• type (string) can be insert, update, remove
• items (array) are items that was inserted, updated or removed

Example:

var fruits = new Arr('apple', 'orange', 'pineapple');

fruits.on('change', function(event) {
  // event
  // {
  //   "type": "insert",
  //   "items": ['mango']
  // }
  
  console.log('fruits list is changed.');
});

fruits.push('mango');

trigger(eventName [, args])

Trigger some event.

var fruits = new Arr('apple', 'orange', 'pineapple');

fruits.on('change', function(event) {
  console.log('fruits list is changed.');
});

fruits.trigger('change');
// fruits list is changed.

Use Cases

Send server updates when Arr is changed.

var products = new Arr(
  {
    id: 1,
    name: 'apple'
  }, 
  {
    id: 2,
    name: 'orange'
  },
  {
    id: 3,
    name: 'pineapple'
  }
);

products.on('change', function(event) {
  // products are changed
  // you can use event.type == 'insert' or 'update' or 'remove' to detect items that you need to update on the server
  
  // $ is link on jQuery
  $.post('/products', products)
    .fail(function() {
      alert('error');
    })
    .done(function(updatedProducts) {
      alert('products are updated');
    });
});

products.push({
  name: 'lime'
});