add keepLines and keepNext support for paragraph formatting

This commit adds it to the three places where paragraph formatting can
be applied right now (directly on the paragraph, paragraph styles, and
bullets/numbering styles). I'm separately adding an entry to the wiki
regarding what these methods do (widow/orphan control)

ts/docx/paragraph/formatting.ts

@@ -1,6 +1,7 @@
 export { Alignment } from "./alignment";
 export { ThematicBreak } from "./border";
 export { Indent } from "./indent";
+export { KeepLines, KeepNext } from "./keep";
 export { PageBreak } from "./page-break";
 export { ParagraphProperties } from "./properties";
 export { ISpacingProperties, Spacing } from "./spacing";

ts/docx/paragraph/index.ts

@@ -8,6 +8,7 @@ import { XmlComponent } from "../xml-components";
 import { Alignment } from "./alignment";
 import { ThematicBreak } from "./border";
 import { Indent } from "./indent";
+import { KeepLines, KeepNext } from "./keep";
 import { PageBreak } from "./page-break";
 import { ParagraphProperties } from "./properties";
 import { ISpacingProperties, Spacing } from "./spacing";
@@ -140,4 +141,14 @@ export class Paragraph extends XmlComponent {
         this.properties.push(new Spacing(params));
         return this;
     };
+
+    public keepNext(): Paragraph {
+        this.properties.push(new KeepNext());
+        return this;
+    }
+
+    public keepLines(): Paragraph {
+        this.properties.push(new KeepLines());
+        return this;
+    }
 }

ts/docx/paragraph/keep.ts

@@ -0,0 +1,13 @@
+import { XmlComponent } from "../xml-components";
+
+export class KeepLines extends XmlComponent {
+    constructor() {
+        super("w:keepLines");
+    }
+}
+
+export class KeepNext extends XmlComponent {
+    constructor() {
+        super("w:keepNext");
+    }
+}

ts/numbering/level.ts

@@ -205,6 +205,16 @@ class LevelBase extends XmlComponent {
         this.addParagraphProperty(new paragraph.Spacing(params));
         return this;
     };
+
+    public keepNext(): Level {
+        this.addParagraphProperty(new paragraph.KeepNext());
+        return this;
+    }
+
+    public keepLines(): Level {
+        this.addParagraphProperty(new paragraph.KeepLines());
+        return this;
+    }
 }
 
 export class Level extends LevelBase {

ts/styles/style/index.ts

@@ -180,6 +180,16 @@ export class ParagraphStyle extends Style {
         this.addParagraphProperty(new paragraph.Spacing(params));
         return this;
     };
+
+    public keepNext(): ParagraphStyle {
+        this.addParagraphProperty(new paragraph.KeepNext());
+        return this;
+    }
+
+    public keepLines(): ParagraphStyle {
+        this.addParagraphProperty(new paragraph.KeepLines());
+        return this;
+    }
 }
 
 export class HeadingStyle extends ParagraphStyle {

ts/tests/docx/paragraph/paragraphTests.ts

@@ -269,4 +269,24 @@ describe("Paragraph", () => {
             });
         });
     });
+
+    describe("#keepLines", () => {
+        it("should set the paragraph keepLines sub-component", () => {
+            paragraph.keepLines();
+            const tree = new Formatter().format(paragraph);
+            expect(tree).to.deep.equal({
+                "w:p": [{"w:pPr": [{"w:keepLines": []}]}],
+            });
+        });
+    });
+
+    describe("#keepNext", () => {
+        it("should set the paragraph keepNext sub-component", () => {
+            paragraph.keepNext();
+            const tree = new Formatter().format(paragraph);
+            expect(tree).to.deep.equal({
+                "w:p": [{"w:pPr": [{"w:keepNext": []}]}],
+            });
+        });
+    });
 });

ts/tests/numberingTest.ts

@@ -222,6 +222,26 @@ describe("AbstractNumbering", () => {
                     ],
                 });
             });
+
+            it("#keepLines", () => {
+                const abstractNumbering = new AbstractNumbering(1);
+                const level = abstractNumbering.createLevel(0, "lowerRoman", "%0.")
+                    .keepLines();
+                const tree = new Formatter().format(level);
+                expect(tree["w:lvl"]).to.include({
+                    "w:pPr": [{"w:keepLines": []}],
+                });
+            });
+
+            it("#keepNext", () => {
+                const abstractNumbering = new AbstractNumbering(1);
+                const level = abstractNumbering.createLevel(0, "lowerRoman", "%0.")
+                    .keepNext();
+                const tree = new Formatter().format(level);
+                expect(tree["w:lvl"]).to.include({
+                    "w:pPr": [{"w:keepNext": []}],
+                });
+            });
         });
 
         describe("formatting methods: run properties", () => {

ts/tests/stylesTest.ts

@@ -326,6 +326,32 @@ describe("ParagraphStyle", () => {
                 ],
             });
         });
+
+        it("#keepLines", () => {
+            const style = new ParagraphStyle("myStyleId")
+                .keepLines();
+            const tree = new Formatter().format(style);
+            expect(tree).to.deep.equal({
+                "w:style": [
+                    {_attr: {"w:type": "paragraph", "w:styleId": "myStyleId"}},
+                    {"w:pPr": [{"w:keepLines": []}]},
+                    {"w:rPr": []},
+                ],
+            });
+        });
+
+        it("#keepNext", () => {
+            const style = new ParagraphStyle("myStyleId")
+                .keepNext();
+            const tree = new Formatter().format(style);
+            expect(tree).to.deep.equal({
+                "w:style": [
+                    {_attr: {"w:type": "paragraph", "w:styleId": "myStyleId"}},
+                    {"w:pPr": [{"w:keepNext": []}]},
+                    {"w:rPr": []},
+                ],
+            });
+        });
     });
 
     describe("formatting methods: run properties", () => {