init

node_modules/common-path-prefix/index.js

@@ -0,0 +1,33 @@
+'use strict'
+const { sep: DEFAULT_SEPARATOR } = require('path')
+
+const determineSeparator = paths => {
+  for (const path of paths) {
+    const match = /(\/|\\)/.exec(path)
+    if (match !== null) return match[0]
+  }
+
+  return DEFAULT_SEPARATOR
+}
+
+module.exports = function commonPathPrefix (paths, sep = determineSeparator(paths)) {
+  const [first = '', ...remaining] = paths
+  if (first === '' || remaining.length === 0) return ''
+
+  const parts = first.split(sep)
+
+  let endOfPrefix = parts.length
+  for (const path of remaining) {
+    const compare = path.split(sep)
+    for (let i = 0; i < endOfPrefix; i++) {
+      if (compare[i] !== parts[i]) {
+        endOfPrefix = i
+      }
+    }
+
+    if (endOfPrefix === 0) return ''
+  }
+
+  const prefix = parts.slice(0, endOfPrefix).join(sep)
+  return prefix.endsWith(sep) ? prefix : prefix + sep
+}