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Array observable

Observables arrays help you keep a collection of DOM elements synced. Observables arrays are automatically initialized when you provide an array to the blocks.observable() method.

var items = blocks.observable([1, 2, 3]);

Observable arrays support all standard JavaScript array methods that you are used to:

  • push
  • pop
  • reverse
  • shift
  • sort
  • splice
  • unshift
  • concat
  • slice
  • join
var items = blocks.observable([1, 2, 3]);
items.push(4);

All of the methods above and some additional methods for easier work with observable arrays are described in the API documentation.

Events

Observable arrays have additional events for tracking when adding and removing items from the array:

  • adding - fires before adding items to the array. Could be canceled by returning false
var items = blocks.observable([3, 5, 7, 9]).on('adding', function (args) {
  // args.items - the items that are going to be added to the array
  // args.index - the index where the items will be added
  // args.type = 'adding'

  return false;
});

// the values will not be added to the array because of the return false in the handler
items.push(11, 13);
  • add - fires after items have been added to the array
var items = blocks.observable([3, 5, 7, 9]).on('add', function (args) {
  // args.items - the items that have been added to the array
  // args.index - the index where the items have been added
  // args.type = 'add'
});

// the values will be added to the end of the array
items.push(11, 13);
  • removing - fires before removing items from the array. Could be canceled by returning false
var items = blocks.observable([3, 5, 7, 9]).on('removing', function (args) {
  // args.items - the items that are going to be removed from the array
  // args.index - the index from where the items will be removed
  // args.type = 'removing'

  return false;
});

// the value will not be removed from the array because of the return false in the handler
items.pop();
  • remove - fires after items have been removed from the array
var items = blocks.observable([3, 5, 7, 9]).on('remove', function (args) {
  // args.items - the items that have been added to the array
  // args.index - the index where the items have been added
  // args.type = 'remove'
});

// the values will be removed from the array
items.pop();