From 9629c8d8d6a01dfda90fbc8d3eefe4eb8f1a8620 Mon Sep 17 00:00:00 2001
From: Jon Ruskin <jonabc@github.com>
Date: Tue, 17 Jan 2023 08:31:36 -0700
Subject: [PATCH] use undefined not null

---
 packages/mermaid/src/diagrams/sequence/svgDraw.js | 8 ++++++--
 packages/mermaid/src/utils.spec.js                | 4 ++--
 packages/mermaid/src/utils.ts                     | 2 +-
 3 files changed, 9 insertions(+), 5 deletions(-)

diff --git a/packages/mermaid/src/diagrams/sequence/svgDraw.js b/packages/mermaid/src/diagrams/sequence/svgDraw.js
index 495865674..220db2209 100644
--- a/packages/mermaid/src/diagrams/sequence/svgDraw.js
+++ b/packages/mermaid/src/diagrams/sequence/svgDraw.js
@@ -218,7 +218,11 @@ export const drawText = function (elem, textData) {
     }
   }
   for (let [i, line] of lines.entries()) {
-    if (textData.textMargin !== undefined && textData.textMargin === 0 && _textFontSize !== null) {
+    if (
+      textData.textMargin !== undefined &&
+      textData.textMargin === 0 &&
+      _textFontSize !== undefined
+    ) {
       dy = i * _textFontSize;
     }
 
@@ -234,7 +238,7 @@ export const drawText = function (elem, textData) {
     if (textData.fontFamily !== undefined) {
       textElem.style('font-family', textData.fontFamily);
     }
-    if (_textFontSizePx !== null) {
+    if (_textFontSizePx !== undefined) {
       textElem.style('font-size', _textFontSizePx);
     }
     if (textData.fontWeight !== undefined) {
diff --git a/packages/mermaid/src/utils.spec.js b/packages/mermaid/src/utils.spec.js
index f8bf613fd..0f0bc1e92 100644
--- a/packages/mermaid/src/utils.spec.js
+++ b/packages/mermaid/src/utils.spec.js
@@ -421,10 +421,10 @@ describe('when parsing font sizes', function () {
   });
 
   it('handles undefined input', function () {
-    expect(utils.parseFontSize(undefined)).toEqual([null, null]);
+    expect(utils.parseFontSize(undefined)).toEqual([undefined, undefined]);
   });
 
   it('handles unparseable input', function () {
-    expect(utils.parseFontSize({ fontSize: 14 })).toEqual([null, null]);
+    expect(utils.parseFontSize({ fontSize: 14 })).toEqual([undefined, undefined]);
   });
 });
diff --git a/packages/mermaid/src/utils.ts b/packages/mermaid/src/utils.ts
index a4ef5f630..876c81543 100644
--- a/packages/mermaid/src/utils.ts
+++ b/packages/mermaid/src/utils.ts
@@ -962,7 +962,7 @@ export const parseFontSize = (fontSize: string | number | undefined): [number?,
   const fontSizeNumber = parseInt(fontSize, 10);
   if (Number.isNaN(fontSizeNumber)) {
     // if a number value can't be parsed, return null for both values
-    return [null, null];
+    return [undefined, undefined];
   } else if (fontSize === String(fontSizeNumber)) {
     // if a string input doesn't contain any units, assume px units
     return [fontSizeNumber, fontSize + 'px'];