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In the last assignment we created this solution with
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our log here where we could add items which get an
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incrementing number and this number then determines whether we have
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a background color which is blue or this white text CSS
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class attached to it.
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Now in the assignment I said that it is one option to
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use an incrementing number in our log.
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Another option might be to use any other.
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Content for example a timestamp,
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but it could be any other text.
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So first of all change this Here in my app
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component typescript file that will no longer push this
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number
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Instead, I will use the timestamp here,
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which we can get with new date.
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Date is a built -in object JavaScript ships with,
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so there is no need to add any import.
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S… Speaker 2 (46_getting_the_index_when_using_ngfor)
Now with that,
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we're pushing new timestamps on this array.
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Can demonstrate this with ng -surf running by simply clicking this
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button here.
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But now everything is blue,
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of course, because our check here now always returns true
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because a string,
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and this is just a string,
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is always deemed as being greater than five.
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So our check doesn't work anymore.
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We can add something to ng4 here too.
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Separated with a semicolon,
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you can extract some extra information.
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The current index or the index of
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the current iteration.
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S… Speaker 2 (46_getting_the_index_when_using_ngfor)
With let,
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you can bind it to any variable name of your choice,
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like i or index,
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whatever you like.
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I will set it to i.
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And then you set equal to index.
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Now equal to index kind of is also like a reserved
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expression,
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you could say.
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It gives you access to the index of the current iteration.
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So in the first loop,
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this will be zero.
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In the second loop,
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so in the second element in this array,
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i will be one and so on.
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Now with this information,
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you can of course update your solution here to no longer check
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if log item is greater or equal than five.
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but if i is greater or equal than four,
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because remember,
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the index starts at zero.
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So let's update both checks like this.
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S… Speaker 2 (46_getting_the_index_when_using_ngfor)
And now with that,
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this should work with any content and not just with incrementing numbers.
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This looks pretty good.
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So that's a tiny addition.
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extracting the index of ng4 just like that.
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S… Speaker 2 (46_getting_the_index_when_using_ngfor)
With that,
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enough about the basics.
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We got a lot of solid knowledge right now.
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Let's use it to set up our course project in the next
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section before we then dive deeper into components and data
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binding.
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Can't wait to see you there.

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