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