// when an optional dep fails to install, we need to remove the branch of the // graph up to the first optionalDependencies, as well as any nodes that are // only required by other nodes in the set. // // This function finds the set of nodes that will need to be removed in that // case. // // Note that this is *only* going to work with trees where calcDepFlags // has been called, because we rely on the node.optional flag. const gatherDepSet = require('./gather-dep-set.js') const optionalSet = node => { if (!node.optional) { return new Set() } // start with the node, then walk up the dependency graph until we // get to the boundaries that define the optional set. since the // node is optional, we know that all paths INTO this area of the // graph are optional, but there may be non-optional dependencies // WITHIN the area. const set = new Set([node]) for (const node of set) { for (const edge of node.edgesIn) { if (!edge.optional) { set.add(edge.from) } } } // now that we've hit the boundary, gather the rest of the nodes in // the optional section. that's the set of dependencies that are only // depended upon by other nodes within the set, or optional dependencies // from outside the set. return gatherDepSet(set, edge => !edge.optional) } module.exports = optionalSet