1const npa = require('npm-package-arg')
2
3// extracted from npm v6 lib/install/realize-shrinkwrap-specifier.js
4const specFromLock = (name, lock, where) => {
5  try {
6    if (lock.version) {
7      const spec = npa.resolve(name, lock.version, where)
8      if (lock.integrity || spec.type === 'git') {
9        return spec
10      }
11    }
12    if (lock.from) {
13      // legacy metadata includes "from", but not integrity
14      const spec = npa.resolve(name, lock.from, where)
15      if (spec.registry && lock.version) {
16        return npa.resolve(name, lock.version, where)
17      } else if (!lock.resolved) {
18        return spec
19      }
20    }
21    if (lock.resolved) {
22      return npa.resolve(name, lock.resolved, where)
23    }
24  } catch {
25    // ignore errors
26  }
27  try {
28    return npa.resolve(name, lock.version, where)
29  } catch {
30    return {}
31  }
32}
33
34module.exports = specFromLock
35