update

package/node_modules/libnpmdiff/lib/index.js

@@ -0,0 +1,62 @@
+const pacote = require('pacote')
+
+const formatDiff = require('./format-diff.js')
+const getTarball = require('./tarball.js')
+const untar = require('./untar.js')
+
+// TODO: we test this condition in the diff command
+// so this error probably doesnt need to be here. Or
+// if it does we should figure out a standard code
+// so we can catch it in the cli and display it consistently
+const argsError = () =>
+  Object.assign(
+    new TypeError('libnpmdiff needs two arguments to compare'),
+    { code: 'EDIFFARGS' }
+  )
+const diff = async (specs, opts = {}) => {
+  if (specs.length !== 2) {
+    throw argsError()
+  }
+
+  const [
+    aManifest,
+    bManifest,
+  ] =
+    await Promise.all(specs.map(spec => pacote.manifest(spec, opts)))
+
+  const versions = {
+    a: aManifest.version,
+    b: bManifest.version,
+  }
+
+  // fetches tarball using pacote
+  const [a, b] = await Promise.all([
+    getTarball(aManifest, opts),
+    getTarball(bManifest, opts),
+  ])
+
+  // read all files
+  // populates `files` and `refs`
+  const {
+    files,
+    refs,
+  } = await untar([
+    {
+      prefix: 'a/',
+      item: a,
+    },
+    {
+      prefix: 'b/',
+      item: b,
+    },
+  ], opts)
+
+  return formatDiff({
+    files,
+    opts,
+    refs,
+    versions,
+  })
+}
+
+module.exports = diff