From 8425cb23e1bc763856dd5afebf7098c024ae15cb Mon Sep 17 00:00:00 2001
From: Harsha Teja Kanna <h7kanna@gmail.com>
Date: Mon, 30 Sep 2024 00:36:09 -0400
Subject: [PATCH] Added link reference 'definition' token type

---
 lib/renderer.mjs              |  2 +-
 lib/rules_block/reference.mjs | 15 +++++++-
 test/misc.mjs                 | 68 +++++++++++++++++++++++++++++++++++
 3 files changed, 83 insertions(+), 2 deletions(-)

diff --git a/lib/renderer.mjs b/lib/renderer.mjs
index a58914c..a3bd58b 100644
--- a/lib/renderer.mjs
+++ b/lib/renderer.mjs
@@ -187,7 +187,7 @@ Renderer.prototype.renderToken = function renderToken (tokens, idx, options) {
   //  - a
   //    >
   //
-  if (token.block && token.nesting !== -1 && idx && tokens[idx - 1].hidden) {
+  if (token.block && token.nesting !== -1 && idx && tokens[idx - 1].hidden && tokens[idx - 1].type !== 'definition') {
     result += '\n'
   }
 
diff --git a/lib/rules_block/reference.mjs b/lib/rules_block/reference.mjs
index 4166286..e1f994a 100644
--- a/lib/rules_block/reference.mjs
+++ b/lib/rules_block/reference.mjs
@@ -190,7 +190,8 @@ export default function reference (state, startLine, _endLine, silent) {
     return false
   }
 
-  const label = normalizeReference(str.slice(1, labelEnd))
+  const label_raw = str.slice(1, labelEnd)
+  const label = normalizeReference(label_raw)
   if (!label) {
     // CommonMark 0.20 disallows empty labels
     return false
@@ -208,5 +209,17 @@ export default function reference (state, startLine, _endLine, silent) {
   }
 
   state.line = nextLine
+
+  const token = state.push('definition', '', 0)
+  token.meta = {
+    label: label_raw,
+    destination: href,
+    title
+  }
+  token.map = [startLine, state.line]
+  token.block = true
+  token.hidden = true
+  token.children = []
+
   return true
 }
diff --git a/test/misc.mjs b/test/misc.mjs
index 9c297e9..0e36c79 100644
--- a/test/misc.mjs
+++ b/test/misc.mjs
@@ -472,3 +472,71 @@ describe('Token attributes', function () {
     assert.strictEqual(t.attrGet('myattr'), 'myvalue')
   })
 })
+
+describe('Definition', function () {
+  function type_filter (tokens, type) {
+    return tokens.filter(function (t) { return t.type === type })
+  }
+
+  it('Should not render link reference definition', function () {
+    const md = markdownit()
+
+    assert.strictEqual(
+      md.render('[foo]: /url "title"\n\n[foo]', {}),
+      '<p><a href="/url" title="title">foo</a></p>\n'
+    )
+  })
+
+  it('Should not render newline after link reference definition', function () {
+    const md = markdownit()
+
+    assert.strictEqual(
+      md.render('[foo]: /url "title"\nbar', {}),
+      '<p>bar</p>\n'
+    )
+  })
+
+  it('Should add meta to link reference definition', function () {
+    const md = markdownit()
+
+    let tokens = md.parse('[foo]: /url "title"\n\n[foo]', {})
+    assert.strictEqual(type_filter(tokens, 'definition').length, 1)
+    tokens = type_filter(tokens, 'definition')
+    assert.deepEqual(
+      tokens[0].meta,
+      { label: 'foo', destination: '/url', title: 'title' }
+    )
+  })
+
+  it('Should add sourcemap info to link reference definition token', function () {
+    const md = markdownit()
+
+    let tokens = md.parse("[foo]: /url '\ntitle\nline1\nline2\n'\n\n[foo]", {})
+    assert.strictEqual(type_filter(tokens, 'definition').length, 1)
+    tokens = type_filter(tokens, 'definition')
+    assert.deepEqual(
+      tokens[0].map,
+      [0, 5]
+    )
+    assert.deepEqual(
+      tokens[0].meta,
+      { label: 'foo', destination: '/url', title: '\ntitle\nline1\nline2\n' }
+    )
+  })
+
+  it('Empty link destination should be empty string in the link reference definition token', function () {
+    const md = markdownit()
+
+    let tokens = md.parse('[foo]: <>\n\n[foo]', {})
+    assert.strictEqual(type_filter(tokens, 'definition').length, 1)
+    tokens = type_filter(tokens, 'definition')
+    assert.deepEqual(
+      tokens[0].map,
+      [0, 1]
+    )
+    assert.deepEqual(
+      tokens[0].meta,
+      { label: 'foo', destination: '', title: '' }
+    )
+  })
+})