Vue - DOM is not updating when doing .sort() on array - sorting

Question

I am trying to sort some JSON data using Vue. The data gets changed when checking via Vue console debugger, but the actual DOM doesn't get updated.
This is my Vue code:
Array.prototype.unique = function () {
return this.filter(function (value, index, self) {
return self.indexOf(value) === index;
});
};
if (!Array.prototype.last) {
Array.prototype.last = function () {
return this[this.length - 1];
};
};
var vm = new Vue({
el: "#streetleague-news",
data: {
allItems: [],
itemTypes: [],
itemTypesWithHeading: [],
selectedType: "All",
isActive: false,
sortDirection: "newFirst",
paginate: ['sortedItems']
},
created() {
axios.get("/umbraco/api/NewsLibraryApi/getall")
.then(response => {
// JSON responses are automatically parsed.
this.allItems = response.data;
this.itemTypes = this.allItems.filter(function (x) {
return x.Tag != null && x.Tag.length;
}).map(function (x) {
return x.Tag;
}).unique();
});
},
computed: {
isAllActive() {
return this.selectedType === "All";
},
filteredItems: function () {
var _this = this;
return _this.allItems.filter(function (x) {
return _this.selectedType === "All" || x.Tag === _this.selectedType;
});
},
sortedItems: function () {
var _this = this;
var news = _this.filteredItems;
if (_this.sortDirection === 'newFirst') {
news.sort(function (a, b) {
return new Date(b.PostDate) - new Date(a.PostDate);
});
} else {
news.sort(function (a, b) {
return new Date(a.PostDate) - new Date(b.PostDate);
});
}
return news;
}
},
methods: {
onChangePage(sortedItems) {
// update page of items
this.sortedItems = sortedItems;
}
}
});
This is an HTML part:
<paginate class="grid-3 flex" name="sortedItems" :list="sortedItems" :per="12" ref="paginator">
<li class="flex" v-for="item in paginated('sortedItems')">
The bit that seems not to be working is the sortedItems: function () {....
Can anyone see why the DOM is not updating?

Answer 1

The most probable is that sort() method doesn't recognize Date object precedence. Use js timestamp instead:
if (_this.sortDirection === 'newFirst') {
news.sort(function (a, b) {
var dateA = new Date(a.PostDate);
var dateB = new Date(b.PostDate);
return dateB.valueOf() - dateA.valueOf();
});
} else {
news.sort(function (a, b) {
var dateA = new Date(a.PostDate);
var dateB = new Date(b.PostDate);
return dateA.valueOf() - dateB.valueOf();
});
}

Answer 2

Got there eventually - thanks for your help
sortedItems: function () {
var _this = this;
var news = _this.allItems;
if (_this.sortDirection === 'newFirst') {
news.sort(function (a, b) {
var dateA = new Date(a.PostDate);
var dateB = new Date(b.PostDate);
return dateB.valueOf() - dateA.valueOf();
});
} else {
news.sort(function (a, b) {
var dateA = new Date(a.PostDate);
var dateB = new Date(b.PostDate);
return dateA.valueOf() - dateB.valueOf();
})
}
return news.filter(x => {
return _this.selectedType === "All" || x.Tag ===
_this.selectedType;
});
}