Pipeline artifacts are a way to persist build outputs, test results, and other files generated during a pipeline run. They allow you to share data between stages, jobs, and pipelines, and to persist data for longer than the lifetime of a pipeline run. While artifacts can be useful for sharing data between pipeline runs and reducing the time required to download dependencies, they are not a solution for reducing the time required to install JavaScript packages from npm during a pipeline run.
The solution of reducing the pipeline execution time could be achieved by using package caching, which allows you to store and reuse npm packages from previous pipeline runs. There are several package caching options available for Azure Pipelines, including the npm task, the npm cache task, and the npm ci task. All of these options allow you to configure caching for your npm packages, which can significantly reduce the time required to install packages during subsequent pipeline runs.
Another solution could be using a dedicated agent that has those packages already installed, this way the pipeline doesn't have to install them again.
You can find more information on package caching by following this link https://docs.microsoft.com/en-us/azure/devops/pipelines/tasks/package/npm-cache?view=azure-devops