Crawlable Anchors
Come si rende una pagina crawlabile?
Seo main factors
What are Crawlable Anchors
Search engine crawlers are able to follow the links of your website exclusively if they use proper <a> tags with resolvable URLs:

How to use <a> tags properly
If a link is an <a> tag with an href attribute, crawlers will be able to follow it correctly; on the other hand, if the format is different (i.e. without an href tag or other tags relative to a link), crawlers will not follow it: this is due to the script events.
For instance, crawlers can follow:
<a href="https://example.com">
<a href="/relative/path/file">
They can not follow:
<a routerLink="some/path">
<span href="https://example.com">
<a onclick="goto('https://example.com')">
Make sure to link to resolvable URLs
You have to be sure that in the <a> tag you are linking to a valid URL, namely that the crawlers can interact with it, such as:
https://example.com/stuff
/products
/products.php?id=123
What is not considered a valid URL:
javascript:goTo('products')
javascript:window.location.href='/products'
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