From 417d8b9478b01174c7fde62940c26a40249c5a24 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Moritz=20Schmitz=20von=20H=C3=BClst?=
 <moritz@hauptstadtoffice.com>
Date: Wed, 11 Nov 2020 11:59:01 +0100
Subject: [PATCH 1/4] add identifier function

---
 functions/identifier.js      | 10 ++++++++++
 test/functions/identifier.js | 10 ++++++++++
 2 files changed, 20 insertions(+)
 create mode 100644 functions/identifier.js
 create mode 100644 test/functions/identifier.js

diff --git a/functions/identifier.js b/functions/identifier.js
new file mode 100644
index 00000000..db4f62f4
--- /dev/null
+++ b/functions/identifier.js
@@ -0,0 +1,10 @@
+const {t, src} = require('../internal/re')
+const identifier = (version) => {
+    const split = version.split('\.');
+    const valid = split.every(part => new RegExp(`^${src[t.PRERELEASEIDENTIFIER]}$`).test(part));
+    if (!valid) {
+        return null;
+    }
+    return version;
+}
+module.exports = identifier
\ No newline at end of file
diff --git a/test/functions/identifier.js b/test/functions/identifier.js
new file mode 100644
index 00000000..0e121f8c
--- /dev/null
+++ b/test/functions/identifier.js
@@ -0,0 +1,10 @@
+const {test} = require('tap')
+const identifier = require('../../functions/identifier.js')
+
+test('identifier tests', t => {
+    t.equal(identifier('hotfix-410'), 'hotfix-410')
+    t.equal(identifier('hotfix/410'), null)
+    t.equal(identifier('123.123.123'), '123.123.123')
+    t.equal(identifier('007.james.bond'), null)
+    t.end()
+})

From a8a49b87fe6e08a14fad321ab9b43ad62cfce7b4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Moritz=20Schmitz=20von=20H=C3=BClst?=
 <moritz@hauptstadtoffice.com>
Date: Wed, 11 Nov 2020 12:04:49 +0100
Subject: [PATCH 2/4] add docs

---
 README.md | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/README.md b/README.md
index 9bef045a..b9214f94 100644
--- a/README.md
+++ b/README.md
@@ -56,6 +56,7 @@ const semverCompareLoose = require('semver/functions/compare-loose')
 const semverCompareBuild = require('semver/functions/compare-build')
 const semverSort = require('semver/functions/sort')
 const semverRsort = require('semver/functions/rsort')
+const semverIdentifier = require('semver/functions/identifier')
 
 // low-level comparators between versions
 const semverGt = require('semver/functions/gt')
@@ -398,6 +399,7 @@ strings that they parse.
   or comparators intersect.
 * `parse(v)`: Attempt to parse a string as a semantic version, returning either
   a `SemVer` object or `null`.
+* `identifier(v)`: Return a valid prerelease identifier, or null if it's not valid.
 
 ### Comparison
 

From 911dd490fc43366b4ab9dd7e9e224752d6be0629 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Moritz=20Schmitz=20von=20H=C3=BClst?=
 <moritz@hauptstadtoffice.com>
Date: Wed, 11 Nov 2020 12:06:22 +0100
Subject: [PATCH 3/4] add empty line

---
 functions/identifier.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/functions/identifier.js b/functions/identifier.js
index db4f62f4..ae4b480c 100644
--- a/functions/identifier.js
+++ b/functions/identifier.js
@@ -7,4 +7,4 @@ const identifier = (version) => {
     }
     return version;
 }
-module.exports = identifier
\ No newline at end of file
+module.exports = identifier

From aea03ba1e0bc153a0f9f8eb290f5faecf986210d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Moritz=20Schmitz=20von=20H=C3=BClst?=
 <moritz@hauptstadtoffice.com>
Date: Wed, 11 Nov 2020 12:13:36 +0100
Subject: [PATCH 4/4] export function

---
 index.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/index.js b/index.js
index 57e2ae64..b2a646f7 100644
--- a/index.js
+++ b/index.js
@@ -45,4 +45,5 @@ module.exports = {
   intersects: require('./ranges/intersects'),
   simplifyRange: require('./ranges/simplify'),
   subset: require('./ranges/subset'),
+  identifier: require('./functions/identifier'),
 }