Implement "until" keyword in gantt charts

docs/syntax/gantt.md

@@ -67,8 +67,8 @@ gantt
     Create tests for parser             :crit, active, 3d
     Future task in critical line        :crit, 5d
     Create tests for renderer           :2d
-    Add to mermaid                      :1d
-    Functionality added                 :milestone, 2014-01-25, 0d
+    Add to mermaid                      :until isadded
+    Functionality added                 :milestone, isadded, 2014-01-25, 0d
 
     section Documentation
     Describe gantt syntax               :active, a1, after des1, 3d
@@ -100,8 +100,8 @@ gantt
     Create tests for parser             :crit, active, 3d
     Future task in critical line        :crit, 5d
     Create tests for renderer           :2d
-    Add to mermaid                      :1d
-    Functionality added                 :milestone, 2014-01-25, 0d
+    Add to mermaid                      :until isadded
+    Functionality added                 :milestone, isadded, 2014-01-25, 0d
 
     section Documentation
     Describe gantt syntax               :active, a1, after des1, 3d
@@ -114,20 +114,25 @@ gantt
     Add another diagram to demo page    :48h
 ```
 
+> **Note**
+> Support for keyword `until` was added in (v\<MERMAID_RELEASE_VERSION>+). This can be used to define a task which is running until some other specific task or milestone starts.
+
 It is possible to set multiple dependencies separated by space:
 
 ```mermaid-example
 gantt
     apple :a, 2017-07-20, 1w
     banana :crit, b, 2017-07-23, 1d
     cherry :active, c, after b a, 1d
+    kiwi   :d, 2017-07-20, until b c
 ```
 
 ```mermaid
 gantt
     apple :a, 2017-07-20, 1w
     banana :crit, b, 2017-07-23, 1d
     cherry :active, c, after b a, 1d
+    kiwi   :d, 2017-07-20, until b c
 ```
 
 ### Title

packages/mermaid/src/diagrams/gantt/ganttDb.js

@@ -343,6 +343,35 @@
 const getEndDate = function (prevTime, dateFormat, str, inclusive = false) {
   str = str.trim();
 
+  // Test for until
+  const re = /^until\s+([\d\w- ]+)/;
+  const untilStatement = re.exec(str.trim());
+
+  if (untilStatement !== null) {
+    // check all until ids and take the earliest
+    let earliestStartingTask = null;
+    untilStatement[1].split(' ').forEach(function (id) {
+      let task = findTaskById(id);
+      if (task !== undefined) {
+        if (!earliestStartingTask) {
+          earliestStartingTask = task;
+        } else {
+          if (task.startTime < earliestStartingTask.startTime) {
+            earliestStartingTask = task;
+          }
+        }
+      }
+    });
+
+    if (!earliestStartingTask) {
+      const dt = new Date();
+      dt.setHours(0, 0, 0, 0);
+      return dt;
+    } else {
+      return earliestStartingTask.startTime;
+    }
+  }
+
   // Check for actual date
   let mDate = dayjs(str, dateFormat.trim(), true);
   if (mDate.isValid()) {

packages/mermaid/src/diagrams/gantt/ganttDb.spec.ts

@@ -140,10 +140,10 @@ describe('when using the ganttDb', function () {
 
   it('should handle relative start date based on id regardless of sections', function () {
     ganttDb.setDateFormat('YYYY-MM-DD');
-    ganttDb.addSection('testa1');
+    ganttDb.addSection('sec1');
     ganttDb.addTask('test1', 'id1,2013-01-01,2w');
     ganttDb.addTask('test2', 'id2,after id3,1d');
-    ganttDb.addSection('testa2');
+    ganttDb.addSection('sec2');
     ganttDb.addTask('test3', 'id3,after id1,2d');
 
     const tasks = ganttDb.getTasks();
@@ -158,6 +158,58 @@ describe('when using the ganttDb', function () {
     expect(tasks[2].startTime).toEqual(new Date(2013, 0, 15));
     expect(tasks[2].endTime).toEqual(new Date(2013, 0, 17));
   });
+
+  it('should handle relative end date based on id regardless of sections', function () {
+    ganttDb.setDateFormat('YYYY-MM-DD');
+    ganttDb.addSection('sec1');
+    ganttDb.addTask('task1', 'id1,2013-01-01,until id3');
+    ganttDb.addSection('sec2');
+    ganttDb.addTask('task2', 'id2,2013-01-10,until id3');
+    ganttDb.addTask('task3', 'id3,2013-02-01,2d');
+
+    const tasks = ganttDb.getTasks();
+
+    expect(tasks[0].startTime).toEqual(new Date(2013, 0, 1));
+    expect(tasks[0].endTime).toEqual(new Date(2013, 1, 1));
+    expect(tasks[0].id).toEqual('id1');
+    expect(tasks[0].task).toEqual('task1');
+
+    expect(tasks[1].id).toEqual('id2');
+    expect(tasks[1].task).toEqual('task2');
+    expect(tasks[1].startTime).toEqual(new Date(2013, 0, 10));
+    expect(tasks[1].endTime).toEqual(new Date(2013, 1, 1));
+  });
+
+  it('should handle relative start date based on multiple id', function () {
+    ganttDb.setDateFormat('YYYY-MM-DD');
+    ganttDb.addSection('sec1');
+    ganttDb.addTask('task1', 'id1,after id2 id3 id4,1d');
+    ganttDb.addTask('task2', 'id2,2013-01-01,1d');
+    ganttDb.addTask('task3', 'id3,2013-02-01,3d');
+    ganttDb.addTask('task4', 'id4,2013-02-01,2d');
+
+    const tasks = ganttDb.getTasks();
+
+    expect(tasks[0].endTime).toEqual(new Date(2013, 1, 5));
+    expect(tasks[0].id).toEqual('id1');
+    expect(tasks[0].task).toEqual('task1');
+  });
+
+  it('should handle relative end date based on multiple id', function () {
+    ganttDb.setDateFormat('YYYY-MM-DD');
+    ganttDb.addSection('sec1');
+    ganttDb.addTask('task1', 'id1,2013-01-01,until id2 id3 id4');
+    ganttDb.addTask('task2', 'id2,2013-01-11,1d');
+    ganttDb.addTask('task3', 'id3,2013-02-10,1d');
+    ganttDb.addTask('task4', 'id4,2013-02-12,1d');
+
+    const tasks = ganttDb.getTasks();
+
+    expect(tasks[0].endTime).toEqual(new Date(2013, 0, 11));
+    expect(tasks[0].id).toEqual('id1');
+    expect(tasks[0].task).toEqual('task1');
+  });
+
   it('should ignore weekends', function () {
     ganttDb.setDateFormat('YYYY-MM-DD');
     ganttDb.setExcludes('weekends 2019-02-06,friday');

packages/mermaid/src/docs/syntax/gantt.md

@@ -49,8 +49,8 @@ gantt
     Create tests for parser             :crit, active, 3d
     Future task in critical line        :crit, 5d
     Create tests for renderer           :2d
-    Add to mermaid                      :1d
-    Functionality added                 :milestone, 2014-01-25, 0d
+    Add to mermaid                      :until isadded
+    Functionality added                 :milestone, isadded, 2014-01-25, 0d
 
     section Documentation
     Describe gantt syntax               :active, a1, after des1, 3d
@@ -63,13 +63,18 @@ gantt
     Add another diagram to demo page    :48h
 ```
 
+```note
+Support for keyword `until` was added in (v<MERMAID_RELEASE_VERSION>+). This can be used to define a task which is running until some other specific task or milestone starts.
+```
+
 It is possible to set multiple dependencies separated by space:
 
 ```mermaid-example
 gantt
     apple :a, 2017-07-20, 1w
     banana :crit, b, 2017-07-23, 1d
     cherry :active, c, after b a, 1d
+    kiwi   :d, 2017-07-20, until b c
 ```
 
 ### Title