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Strict inequality operator
Great job! Now highlighting has been added to the news stories from the category that has been selected in the filter. When a user selects a category from the list, only news stories from the selected category should be displayed on the page, and the remaining news stories from all other categories should disappear.
In order to make the news story disappear from the page, you need to add the hidden class to it. Now we are adding a class that is responsible for adding a highlight to those news stories whose categories match the filter value. But how can we do the opposite, namely add a class to news stories whose categories differ? To do this, we use the strict inequality operator. It is indicated by an exclamation mark and two equal signs:
'a' !== 'a'; // Result: false
'a' !== 'b'; // Result: trueThe strict inequality operator performs the exact opposite function of the strict equality operator. If the values are equal, it will return false, and if they are not equal, then it will return true.
Let’s continue to deploy filtering on our news site. Change the condition in the if statement so that the color highlighting is added to news stories from all categories except for the selected one. Then change the highlight class that is responsible for highlighting to the hidden class. This class will hide all of the extra news stories. After that, check that the news items from the unselected categories are in fact hidden.
JavaScript also has a non-strict inequality operator: !=. We will talk about how it differs from the strict inequality operator in one of the following chapters.
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<time datetime="2020-03-24">March 24, 2020</time>
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<time datetime="2020-03-19">February 19, 2020</time>
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<p>The editors of Flashnews! have prepared a gift for their subscribers…</p>
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<time datetime="2020-02-18">February 18, 2020</time>
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<time datetime="2019-12-22">December 22, 2019</time>
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<p>Studies show that if you do more, you can actually get more done.</p>
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<time datetime="2019-10-12">October 12, 2019</time>
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<p>Controlling the quadcopter allows you to develop agility, spatial thinking, and the ability to climb trees…
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<time datetime="2019-11-21">November 21, 2019</time>
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<h3>Infinite loops: It’s time to end them</h3>
<p>British scientists have discovered that the ability of software to function directly depends on the presence of infinite loops in it.</p>
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<time datetime="2019-10-16">October 16, 2019</time>
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<time datetime="2019-12-22">December 22, 2019</time>
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<h3>New graphics library</h3>
<p>Now you can create a dashboard in just a matter of seconds.</p>
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<time datetime="2019-10-14">October 14, 2019</time>
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<p>No one expected that THIS was going on behind the closed doors…</p>
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<time datetime="2019-10-13">October 13, 2019</time>
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let articles = document.querySelectorAll('.news-block');
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filter.onchange = function () {
for (let article of articles) {
if (article.dataset.category === filter.value) {
article.classList.add('highlight');
}
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tileViewButton.classList.remove('view-checked');
newsList.classList.remove('list-tiles-view');
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Thanks! We’ll fix everything at once!
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- On line 6, replace the strict equality operator with the strict inequality operator.
- In the mini-browser change the filter value to “Games”. Please note how news stories from all categories except the selected one are now highlighted.
- On line 7, change the
highlightclass to thehiddenclass. - In the mini-browser change the filter value to “Games” and then to “IT”. Please note how all of the news stories have disappeared from the page.
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