node_modules/npm/lib/view.js

// npm view [pkg [pkg ...]]

module.exports = view
view.usage = "npm view pkg[@version] [<field>[.subfield]...]"

var npm = require("./npm.js")
  , readJson = require("read-package-json")
  , log = require("npmlog")
  , util = require("util")
  , semver = require("semver")
  , mapToRegistry = require("./utils/map-to-registry.js")
  , npa = require("npm-package-arg")
  , path = require("path")

view.completion = function (opts, cb) {
  if (opts.conf.argv.remain.length <= 2) {
    // FIXME: there used to be registry completion here, but it stopped making
    // sense somewhere around 50,000 packages on the registry
    return cb()
  }
  // have the package, get the fields.
  var tag = npm.config.get("tag")
  mapToRegistry(opts.conf.argv.remain[2], npm.config, function (er, uri, auth) {
    if (er) return cb(er)

    npm.registry.get(uri, { auth : auth }, function (er, d) {
      if (er) return cb(er)
      var dv = d.versions[d["dist-tags"][tag]]
        , fields = []
      d.versions = Object.keys(d.versions).sort(semver.compareLoose)
      fields = getFields(d).concat(getFields(dv))
      cb(null, fields)
    })
  })

  function getFields (d, f, pref) {
    f = f || []
    if (!d) return f
    pref = pref || []
    Object.keys(d).forEach(function (k) {
      if (k.charAt(0) === "_" || k.indexOf(".") !== -1) return
      var p = pref.concat(k).join(".")
      f.push(p)
      if (Array.isArray(d[k])) {
        d[k].forEach(function (val, i) {
          var pi = p + "[" + i + "]"
          if (val && typeof val === "object") getFields(val, f, [p])
          else f.push(pi)
        })
        return
      }
      if (typeof d[k] === "object") getFields(d[k], f, [p])
    })
    return f
  }
}

function view (args, silent, cb) {
  if (typeof cb !== "function") cb = silent, silent = false

  if (!args.length) args = ["."]

  var pkg = args.shift()
    , nv = npa(pkg)
    , name = nv.name
    , local = (name === "." || !name)

  if (npm.config.get("global") && local) {
    return cb(new Error("Cannot use view command in global mode."))
  }

  if (local) {
    var dir = npm.prefix
    readJson(path.resolve(dir, "package.json"), function (er, d) {
      d = d || {}
      if (er && er.code !== "ENOENT" && er.code !== "ENOTDIR") return cb(er)
      if (!d.name) return cb(new Error("Invalid package.json"))

      var p = d.name
      nv = npa(p)
      if (pkg && ~pkg.indexOf("@")) {
        nv.rawSpec = pkg.split("@")[pkg.indexOf("@")]
      }

      fetchAndRead(nv, args, silent, cb)
    })
  } else {
    fetchAndRead(nv, args, silent, cb)
  }
}

function fetchAndRead (nv, args, silent, cb) {
  // get the data about this package
  var name = nv.name
    , version = nv.rawSpec || npm.config.get("tag")

  mapToRegistry(name, npm.config, function (er, uri, auth) {
    if (er) return cb(er)

    npm.registry.get(uri, { auth : auth }, function (er, data) {
      if (er) return cb(er)
      if (data["dist-tags"] && data["dist-tags"].hasOwnProperty(version)) {
        version = data["dist-tags"][version]
      }

      if (data.time && data.time.unpublished) {
        var u = data.time.unpublished
        er = new Error("Unpublished by " + u.name + " on " + u.time)
        er.statusCode = 404
        er.code = "E404"
        er.pkgid = data._id
        return cb(er, data)
      }


      var results = []
        , error = null
        , versions = data.versions || {}
      data.versions = Object.keys(versions).sort(semver.compareLoose)
      if (!args.length) args = [""]

      // remove readme unless we asked for it
      if (-1 === args.indexOf("readme")) {
        delete data.readme
      }

      Object.keys(versions).forEach(function (v) {
        if (semver.satisfies(v, version, true)) args.forEach(function (args) {
          // remove readme unless we asked for it
          if (-1 === args.indexOf("readme")) {
            delete versions[v].readme
          }
          results.push(showFields(data, versions[v], args))
        })
      })
      results = results.reduce(reducer, {})
      var retval = results

      if (args.length === 1 && args[0] === "") {
        retval = cleanBlanks(retval)
        log.silly("cleanup", retval)
      }

      if (error || silent) cb(error, retval)
      else printData(results, data._id, cb.bind(null, error, retval))
    })
  })
}

function cleanBlanks (obj) {
  var clean = {}
  Object.keys(obj).forEach(function (version) {
    clean[version] = obj[version][""]
  })
  return clean
}

function reducer (l, r) {
  if (r) Object.keys(r).forEach(function (v) {
    l[v] = l[v] || {}
    Object.keys(r[v]).forEach(function (t) {
      l[v][t] = r[v][t]
    })
  })
  return l
}

// return whatever was printed
function showFields (data, version, fields) {
  var o = {}
  ;[data, version].forEach(function (s) {
    Object.keys(s).forEach(function (k) {
      o[k] = s[k]
    })
  })
  return search(o, fields.split("."), version.version, fields)
}

function search (data, fields, version, title) {
  var field
    , tail = fields
  while (!field && fields.length) field = tail.shift()
  fields = [field].concat(tail)
  var o
  if (!field && !tail.length) {
    o = {}
    o[version] = {}
    o[version][title] = data
    return o
  }
  var index = field.match(/(.+)\[([^\]]+)\]$/)
  if (index) {
    field = index[1]
    index = index[2]
    if (data.field && data.field.hasOwnProperty(index)) {
      return search(data[field][index], tail, version, title)
    } else {
      field = field + "[" + index + "]"
    }
  }
  if (Array.isArray(data)) {
    if (data.length === 1) {
      return search(data[0], fields, version, title)
    }
    var results = []
    data.forEach(function (data, i) {
      var tl = title.length
        , newt = title.substr(0, tl-(fields.join(".").length) - 1)
               + "["+i+"]" + [""].concat(fields).join(".")
      results.push(search(data, fields.slice(), version, newt))
    })
    results = results.reduce(reducer, {})
    return results
  }
  if (!data.hasOwnProperty(field)) return undefined
  data = data[field]
  if (tail.length) {
    if (typeof data === "object") {
      // there are more fields to deal with.
      return search(data, tail, version, title)
    } else {
      return new Error("Not an object: "+data)
    }
  }
  o = {}
  o[version] = {}
  o[version][title] = data
  return o
}

function printData (data, name, cb) {
  var versions = Object.keys(data)
    , msg = ""
    , includeVersions = versions.length > 1
    , includeFields

  versions.forEach(function (v) {
    var fields = Object.keys(data[v])
    includeFields = includeFields || (fields.length > 1)
    fields.forEach(function (f) {
      var d = cleanup(data[v][f])
      if (includeVersions || includeFields || typeof d !== "string") {
        d = cleanup(data[v][f])
        d = npm.config.get("json")
          ? JSON.stringify(d, null, 2)
          : util.inspect(d, false, 5, npm.color)
      } else if (typeof d === "string" && npm.config.get("json")) {
        d = JSON.stringify(d)
      }
      if (f && includeFields) f += " = "
      if (d.indexOf("\n") !== -1) d = " \n" + d
      msg += (includeVersions ? name + "@" + v + " " : "")
           + (includeFields ? f : "") + d + "\n"
    })
  })

  // preserve output symmetry by adding a whitespace-only line at the end if
  // there's one at the beginning
  if (/^\s*\n/.test(msg)) msg += "\n"

  // print directly to stdout to not unnecessarily add blank lines
  process.stdout.write(msg)

  cb(null, data)
}
function cleanup (data) {
  if (Array.isArray(data)) {
    if (data.length === 1) {
      data = data[0]
    } else {
      return data.map(cleanup)
    }
  }
  if (!data || typeof data !== "object") return data

  if (typeof data.versions === "object"
      && data.versions
      && !Array.isArray(data.versions)) {
    data.versions = Object.keys(data.versions || {})
  }

  var keys = Object.keys(data)
  keys.forEach(function (d) {
    if (d.charAt(0) === "_") delete data[d]
    else if (typeof data[d] === "object") data[d] = cleanup(data[d])
  })
  keys = Object.keys(data)
  if (keys.length <= 3
      && data.name
      && (keys.length === 1
          || keys.length === 3 && data.email && data.url
          || keys.length === 2 && (data.email || data.url))) {
    data = unparsePerson(data)
  }
  return data
}
function unparsePerson (d) {
  if (typeof d === "string") return d
  return d.name
       + (d.email ? " <"+d.email+">" : "")
       + (d.url ? " ("+d.url+")" : "")
}