name : gather-dep-set.js // Given a set of nodes in a tree, and a filter function to test // incoming edges to the dep set that should be ignored otherwise. // // find the set of deps that are only depended upon by nodes in the set, or // their dependencies, or edges that are ignored. // // Used when figuring out what to prune when replacing a node with a newer // version, or when an optional dep fails to install. const gatherDepSet = (set, edgeFilter) => { const deps = new Set(set) // add the full set of dependencies. note that this loop will continue // as the deps set increases in size. for (const node of deps) { for (const edge of node.edgesOut.values()) { if (edge.to && edgeFilter(edge)) { deps.add(edge.to) } } } // now remove all nodes in the set that have a dependant outside the set // if any change is made, then re-check // continue until no changes made, or deps set evaporates fully. let changed = true while (changed === true && deps.size > 0) { changed = false for (const dep of deps) { for (const edge of dep.edgesIn) { if (!deps.has(edge.from) && edgeFilter(edge)) { changed = true deps.delete(dep) break } } } } return deps } module.exports = gatherDepSet