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Fetchers are the component tasked from taking a locator and fetching its file data from whatever location the fetcher deems right. For example, the npm fetcher would download them from the npm registry while the workspace fetcher would simply return an plain link to the filesystem.

Implemented by




  • This function must return a object describing where the package manager can find the data for the specified package on disk.

    The return value is a more complex than a regular path (cf FetchResult) because the fetchers are allowed to return virtual paths that point to things that don't actually exist (for example directories stored within zip archives).


    Returns Promise<FetchResult>


  • This function must return the local path for the given package. The local path is the one that's used to resolve relative dependency sources, for example "file:./foo".


    Returns null | PortablePath


  • This function must return true if the specified locator is understood by this resolver (only its syntax is checked, it doesn't have to be valid and it's fine if the fetch ends up returning a 404).


    Returns boolean