causalityjs/test/array-splices.js

A library for reactive programming based on Javascript proxies.

'use strict';
require = require("esm")(module);
const {c,resetObjectIds,repeat,trace} = require("../causality.js");
const assert = require('assert');
//const log = console.log.bind(console);
trace.nestedRepeater = false;

describe("array-splices", function(){
	resetObjectIds();
  
	var result;
	var observedArray = c(['a', 'b', 'c']);
	var observedArray2 = c(['d', 'e', 'f']);

  observedArray.observe(
		function(event) {
      //console.log('first observer');
			result = event;
		}
  );

	it('should report changes', function(){
		observedArray[1] = 'z';
    const expected1 = { type: 'splice', index: 1, removed: ['b'], added: [ 'z' ], objectId: 1};
    expected1.object = observedArray;
		assert.deepEqual( result, expected1 );

    const expected2 = { type: 'splice', index: 3, removed: null, added: [ 'last' ], objectId: 1};
    expected2.object = observedArray;

		observedArray.push('last');
		assert.deepEqual( result, expected2 );

	})

  it('should report shrinked array', function(){
    observedArray.splice(2);
    const expected1 = { type: 'splice', index: 2, removed: ['c','last'], added: [], objectId: 1};
    expected1.object = observedArray;
		assert.deepEqual( result, expected1 );
  });

  it('chained observers of large arrays', function(){
    observedArray.observe(
		  function(event) {
        repeat(function(){
          if( observedArray.length > 20 ) return;
        });

      }
    );
    
    
    let result;
    repeat(function(){
      if( observedArray.length > 505  )
      {
        if( result ) return;
        result = [... observedArray];
        
        assert.equal( result[1], 505 );
        return;
      }

      repeat(function(){
        observedArray.splice(1,0,observedArray.length);
      });
    });
  });

});