prefetching-dependencies: Add yarn (JavaScript) to supported package …

…managers

Signed-off-by: Michal Šoltis <[email protected]>

docs/modules/ROOT/pages/how-tos/configuring/prefetching-dependencies.adoc

@@ -21,6 +21,9 @@ For every build, Cachi2 generates a software bill of materials (SBOM) where all
 |xref:npm[npm]
 |`JavaScript`
 
+|xref:yarn[yarn]
+|`JavaScript`
+
 |xref:bundler[bundler]
 |`Ruby`
 
@@ -301,6 +304,31 @@ spec:
 * From the {ProductName} *Applications* view, go to *Activity > Latest commits*.
 //include::../partials/con_hermetic_verification.adoc[]
 
+== [[yarn]]Enabling prefetch builds for `yarn`
+
+Supported versions: 1.x and 3.x. Cachi2 automatically detects the version of `yarn` and fetches any dependencies you declare in your `package.json` and `yarn.lock` project files.
+
+.Prerequisites
+
+* You have an up-to-date `yarn.lock` file in your source repository. To make sure that you have the latest `yarn.lock` file, or to create a lockfile, run the `yarn install` command. If `yarn.lock` is not up-to-date, Cachi2 will not fetch the dependencies.
+
+.Procedure
+
+To prefetch dependencies for a component build, complete the following steps:
+
+. Go to the `.tekton` directory and find the `.yaml` files related to the `*pull request*` and `*push*` processes.
+. Configure the hermetic pipeline by adding the following parameters in both `.yaml` files:
+
++
+[source,yaml]
+----
+spec:
+  params:
+    - ...
+    - name: prefetch-input
+      value: '{"type": "yarn", "path": "."}'
+----
+
 == [[bundler]]Enabling prefetch builds for `bundler`
 
 .Prerequisites