Add support for ternaries in marker labels (#5857)

Add support for ternaries in marker labels, eg `"{marker.data.canceled ? '❌' :  ''} {marker.data.delay}"`. What to know:

1. The conditional clause can refer to payload fields only, ie `marker.data.*`.
2. The condition is checked for truthiness only, no other conditional operator can be used. Truthiness = classical JS truthiness, ie not null/undefined/empty.
3. The true/false branches should be single-quoted string literals, `"marker.data.* ? 'yes' :  'no'"`.

Author: fatadel

src/profile-logic/marker-schema.ts

@@ -98,6 +98,9 @@ export function getSchemaFromMarker(
   return schemaName ? (markerSchemaByName[schemaName] ?? null) : null;
 }
 
+// Matches ternary expressions inside marker labels, ie {marker.data.field ? 'truthy' : 'falsy'}
+const TERNARY_RE = /^\s*([\w.]+)\s*\?\s*'([^']*)'\s*:\s*'([^']*)'\s*$/;
+
 /**
  * Marker schema can create a dynamic tooltip label. For instance a schema with
  * a `tooltipLabel` field of "Event at {marker.data.url}" would create a label based
@@ -142,8 +145,9 @@ export function parseLabel(
     console.error(oneLine`
       Error processing the label "${label}" because of the ${part}.
       Currently the labels in the marker schema take the form of
-      "marker.data.keyName" or "marker.startTime". No other type
-      of access is currently supported.
+      "marker.data.keyName", "marker.startTime", or a ternary like
+      "marker.data.keyName ? 'yes' : 'no'". No other type of access
+      is currently supported.
     `);
     return () => '';
   }
@@ -161,6 +165,29 @@ export function parseLabel(
       // Given: "Marker information: {marker.name} – {marker.data.info}"
       // Handle:                      ^^^^^^^^^^^     ^^^^^^^^^^^^^^^^
 
+      // Check for a ternary expression:
+      // Given: "{marker.data.canceled ? '❌' : ''} {marker.data.delay}"
+      // Handle:  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+      //
+      // Only marker.data.* fields are supported as conditions. The true/false
+      // branches must be single-quoted string literals.
+      const ternaryMatch = part.match(TERNARY_RE);
+      if (ternaryMatch) {
+        const [, condRef, truthyStr, falsyStr] = ternaryMatch;
+        const condKeys = condRef.split('.');
+        if (
+          condKeys.length === 3 &&
+          condKeys[0] === 'marker' &&
+          condKeys[1] === 'data' &&
+          condKeys[2]
+        ) {
+          const condPayloadKey = condKeys[2];
+          return (marker) =>
+            (marker.data as any)?.[condPayloadKey] ? truthyStr : falsyStr;
+        }
+        return parseError(label, part);
+      }
+
       const keys = part.trim().split('.');
 
       if (keys.length !== 2 && keys.length !== 3) {

src/test/unit/__snapshots__/marker-schema.test.ts.snap

@@ -259,31 +259,31 @@ Array [
 exports[`marker schema labels parseErrors errors if looking up into a part of the marker that does not exist 1`] = `
 Array [
   Array [
-    "Error processing the label \\"Parse error: \\"{marker.nothing}\\"\\" because of the marker.nothing. Currently the labels in the marker schema take the form of \\"marker.data.keyName\\" or \\"marker.startTime\\". No other type of access is currently supported.",
+    "Error processing the label \\"Parse error: \\"{marker.nothing}\\"\\" because of the marker.nothing. Currently the labels in the marker schema take the form of \\"marker.data.keyName\\", \\"marker.startTime\\", or a ternary like \\"marker.data.keyName ? 'yes' : 'no'\\". No other type of access is currently supported.",
   ],
 ]
 `;
 
 exports[`marker schema labels parseErrors errors if not looking up into a marker 1`] = `
 Array [
   Array [
-    "Error processing the label \\"Parse error: \\"{duration}\\"\\" because of the duration. Currently the labels in the marker schema take the form of \\"marker.data.keyName\\" or \\"marker.startTime\\". No other type of access is currently supported.",
+    "Error processing the label \\"Parse error: \\"{duration}\\"\\" because of the duration. Currently the labels in the marker schema take the form of \\"marker.data.keyName\\", \\"marker.startTime\\", or a ternary like \\"marker.data.keyName ? 'yes' : 'no'\\". No other type of access is currently supported.",
   ],
 ]
 `;
 
 exports[`marker schema labels parseErrors errors when accessing random properties 1`] = `
 Array [
   Array [
-    "Error processing the label \\"Parse error: \\"{property.value}\\"\\" because of the property.value. Currently the labels in the marker schema take the form of \\"marker.data.keyName\\" or \\"marker.startTime\\". No other type of access is currently supported.",
+    "Error processing the label \\"Parse error: \\"{property.value}\\"\\" because of the property.value. Currently the labels in the marker schema take the form of \\"marker.data.keyName\\", \\"marker.startTime\\", or a ternary like \\"marker.data.keyName ? 'yes' : 'no'\\". No other type of access is currently supported.",
   ],
 ]
 `;
 
 exports[`marker schema labels parseErrors errors when accessing twice into a payload 1`] = `
 Array [
   Array [
-    "Error processing the label \\"Parse error: \\"{marker.data.duration.extra}\\"\\" because of the marker.data.duration.extra. Currently the labels in the marker schema take the form of \\"marker.data.keyName\\" or \\"marker.startTime\\". No other type of access is currently supported.",
+    "Error processing the label \\"Parse error: \\"{marker.data.duration.extra}\\"\\" because of the marker.data.duration.extra. Currently the labels in the marker schema take the form of \\"marker.data.keyName\\", \\"marker.startTime\\", or a ternary like \\"marker.data.keyName ? 'yes' : 'no'\\". No other type of access is currently supported.",
   ],
 ]
 `;

src/test/unit/marker-schema.test.ts

@@ -172,6 +172,81 @@ describe('marker schema labels', function () {
     expect(console.error).toHaveBeenCalledTimes(0);
   });
 
+  describe('ternary expressions', function () {
+    it('returns the truthy string when the field is truthy', function () {
+      expect(
+        applyLabel({
+          label: "{marker.data.canceled ? '❌' : ''}",
+          schemaFields: [
+            { key: 'canceled', label: 'Canceled', format: 'string' },
+          ],
+          payload: { canceled: true },
+        })
+      ).toEqual('❌');
+      expect(console.error).toHaveBeenCalledTimes(0);
+    });
+
+    it('returns the falsy string when the field is falsy', function () {
+      expect(
+        applyLabel({
+          label: "{marker.data.canceled ? '❌' : ''}",
+          schemaFields: [
+            { key: 'canceled', label: 'Canceled', format: 'string' },
+          ],
+          payload: { canceled: false },
+        })
+      ).toEqual('');
+      expect(console.error).toHaveBeenCalledTimes(0);
+    });
+
+    it('returns the falsy string when the field is absent from the payload', function () {
+      expect(
+        applyLabel({
+          label: "{marker.data.canceled ? '❌' : ''}",
+          schemaFields: [],
+          payload: {},
+        })
+      ).toEqual('');
+      expect(console.error).toHaveBeenCalledTimes(0);
+    });
+
+    it('returns the falsy string when there is no payload', function () {
+      expect(
+        applyLabel({
+          label: "{marker.data.canceled ? 'yes' : 'no'}",
+          schemaFields: [],
+          payload: null,
+        })
+      ).toEqual('no');
+      expect(console.error).toHaveBeenCalledTimes(0);
+    });
+
+    it('can mix a ternary with regular field lookups', function () {
+      expect(
+        applyLabel({
+          label: "{marker.data.canceled ? '❌' : ''} {marker.data.delay}",
+          schemaFields: [
+            { key: 'canceled', label: 'Canceled', format: 'string' },
+            { key: 'delay', label: 'Delay', format: 'milliseconds' },
+          ],
+          payload: { canceled: true, delay: 250 },
+        })
+      ).toEqual('❌ 250ms');
+      expect(console.error).toHaveBeenCalledTimes(0);
+    });
+
+    it('errors when the condition is not a marker.data.* reference', function () {
+      expect(
+        applyLabel({
+          label: "{marker.name ? 'yes' : 'no'}",
+          schemaFields: [],
+          payload: {},
+        })
+      ).toEqual('');
+      expect(console.error).toHaveBeenCalledTimes(1);
+    });
+  });
+
   describe('parseErrors', function () {
     function testParseError(label: string) {
       expect(