* first action! (#1)

node_modules/tar/lib/update.js

@@ -0,0 +1,36 @@
+'use strict'
+
+// tar -u
+
+const hlo = require('./high-level-opt.js')
+const r = require('./replace.js')
+// just call tar.r with the filter and mtimeCache
+
+const u = module.exports = (opt_, files, cb) => {
+  const opt = hlo(opt_)
+
+  if (!opt.file)
+    throw new TypeError('file is required')
+
+  if (opt.gzip)
+    throw new TypeError('cannot append to compressed archives')
+
+  if (!files || !Array.isArray(files) || !files.length)
+    throw new TypeError('no files or directories specified')
+
+  files = Array.from(files)
+
+  mtimeFilter(opt)
+  return r(opt, files, cb)
+}
+
+const mtimeFilter = opt => {
+  const filter = opt.filter
+
+  if (!opt.mtimeCache)
+    opt.mtimeCache = new Map()
+
+  opt.filter = filter ? (path, stat) =>
+    filter(path, stat) && !(opt.mtimeCache.get(path) > stat.mtime)
+    : (path, stat) => !(opt.mtimeCache.get(path) > stat.mtime)
+}