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I have 2 arrays, one is newVal and the other is origVal define
orig:
[
{"ListingId":1762276,"Rating":3,"ListPrice":7411828,"PropertyType":"Residential"},
{"ListingId":1826692,"Rating":3,"ListPrice":650000,"PropertyType":"Residential"},
{"ListingId":1833283,"Rating":4,"ListPrice":950000,"PropertyType":"Residential"},
{"ListingId":1832134,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"},
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"},
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"}
]
new:
[
{"ListingId":1762276,"Rating":2,"ListPrice":7411828,"PropertyType":"Residential"},
{"ListingId":1826692,"Rating":3,"ListPrice":650000,"PropertyType":"Residential"},
{"ListingId":1833283,"Rating":4,"ListPrice":950000,"PropertyType":"Residential"},
{"ListingId":1832134,"Rating":3,"ListPrice":850000,"PropertyType":"Residential"},
{"ListingId":1829932,"Rating":4,"ListPrice":750000,"PropertyType":"Residential"},
{"ListingId":1827548,"Rating":5,"ListPrice":650000,"PropertyType":"Residential"}
]
If I change one of the ratings in new, how might I detect that change, and retrieve the changed object?
There will only be one change at a time, although I don't think that matters.
FYI: These arrays are being produced from an Anjularjs watchcollection
$scope.$watchCollection('items', function (new, old) {
}, true);
Thank you, Stephen
962
Programmers who wish to compare the contents of two arrays must use the static two-argument Arrays. equals() method. This method considers two arrays equivalent if both arrays contain the same number of elements, and all corresponding pairs of elements in the two arrays are equivalent, according to Object. equals() .
Using Arrays. equals(array1, array2) methods − This method iterates over each value of an array and compare using equals method. Using Arrays. deepEquals(array1, array2) methods − This method iterates over each value of an array and deep compare using any overridden equals method.
JavaScript finding non-matching values in two arrays The code will look like this. const array1 = [1, 2, 3, 4, 5, 6]; const array2 = [1, 2, 3, 4, 5, 6, 7, 8, 9]; const output = array2. filter(function (obj) { return array1. indexOf(obj) === -1; }); console.
If the order does not change, a simple iteration will do it. Underscore provides the find method for this task:
var changedObj = _.find(newVal, function(obj, index) {
return obj.Rating != oldVal[index].Rating;
});
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