Introduce some functional programming techniques

src/file/paragraph/run/field.ts

@@ -1,26 +1,32 @@
 import { XmlAttributeComponent, XmlComponent } from "file/xml-components";
 
-class FidCharAttrs extends XmlAttributeComponent<{ type: "begin" | "end" | "separate"; dirty?: boolean }> {
-    protected xmlKeys = { type: "w:fldCharType", dirty: "w:dirty" };
+enum FieldCharacterType {
+    BEGIN = "begin",
+    END = "end",
+    SEPARATE = "separate",
+}
+
+class FidCharAttrs extends XmlAttributeComponent<{ readonly type: FieldCharacterType; readonly dirty?: boolean }> {
+    protected readonly xmlKeys = { type: "w:fldCharType", dirty: "w:dirty" };
 }
 
 export class Begin extends XmlComponent {
     constructor(dirty?: boolean) {
         super("w:fldChar");
-        this.root.push(new FidCharAttrs({ type: "begin", dirty }));
+        this.root.push(new FidCharAttrs({ type: FieldCharacterType.BEGIN, dirty }));
     }
 }
 
 export class Separate extends XmlComponent {
     constructor(dirty?: boolean) {
         super("w:fldChar");
-        this.root.push(new FidCharAttrs({ type: "separate", dirty }));
+        this.root.push(new FidCharAttrs({ type: FieldCharacterType.SEPARATE, dirty }));
     }
 }
 
 export class End extends XmlComponent {
     constructor(dirty?: boolean) {
         super("w:fldChar");
-        this.root.push(new FidCharAttrs({ type: "end", dirty }));
+        this.root.push(new FidCharAttrs({ type: FieldCharacterType.END, dirty }));
     }
 }

src/file/paragraph/run/page-number.ts

@@ -1,13 +1,14 @@
+import { SpaceType } from "file/space-type";
 import { XmlAttributeComponent, XmlComponent } from "file/xml-components";
 
-class TextAttributes extends XmlAttributeComponent<{ space: "default" | "preserve" }> {
-    protected xmlKeys = { space: "xml:space" };
+class TextAttributes extends XmlAttributeComponent<{ readonly space: SpaceType }> {
+    protected readonly xmlKeys = { space: "xml:space" };
 }
 
 export class Page extends XmlComponent {
     constructor() {
         super("w:instrText");
-        this.root.push(new TextAttributes({ space: "preserve" }));
+        this.root.push(new TextAttributes({ space: SpaceType.PRESERVE }));
         this.root.push("PAGE");
     }
 }

src/file/paragraph/run/picture-run.ts

@@ -18,15 +18,7 @@ export class PictureRun extends Run {
         this.root.push(this.drawing);
     }
 
-    public scale(factorX: number, factorY?: number): void {
-        if (!factorX) {
-            factorX = 1;
-        }
-
-        if (!factorY) {
-            factorY = factorX;
-        }
-
+    public scale(factorX: number = 1, factorY: number = factorX): void {
         this.drawing.scale(factorX, factorY);
     }
 }

src/file/paragraph/run/run-components/text.ts

@@ -1,13 +1,14 @@
+import { SpaceType } from "file/space-type";
 import { XmlAttributeComponent, XmlComponent } from "file/xml-components";
 
-class TextAttributes extends XmlAttributeComponent<{ space: "default" | "preserve" }> {
-    protected xmlKeys = { space: "xml:space" };
+class TextAttributes extends XmlAttributeComponent<{ readonly space: SpaceType }> {
+    protected readonly xmlKeys = { space: "xml:space" };
 }
 
 export class Text extends XmlComponent {
     constructor(text: string) {
         super("w:t");
-        this.root.push(new TextAttributes({ space: "preserve" }));
+        this.root.push(new TextAttributes({ space: SpaceType.PRESERVE }));
         if (text) {
             this.root.push(text);
         }

src/file/paragraph/run/run-fonts.ts

@@ -1,15 +1,15 @@
 import { XmlAttributeComponent, XmlComponent } from "file/xml-components";
 
 interface IRunFontAttributesProperties {
-    ascii: string;
-    cs: string;
-    eastAsia: string;
-    hAnsi: string;
-    hint?: string;
+    readonly ascii: string;
+    readonly cs: string;
+    readonly eastAsia: string;
+    readonly hAnsi: string;
+    readonly hint?: string;
 }
 
 class RunFontAttributes extends XmlAttributeComponent<IRunFontAttributesProperties> {
-    protected xmlKeys = {
+    protected readonly xmlKeys = {
         ascii: "w:ascii",
         cs: "w:cs",
         eastAsia: "w:eastAsia",

src/file/paragraph/run/run.ts

@@ -25,7 +25,7 @@ import { Underline } from "./underline";
 import { XmlComponent } from "file/xml-components";
 
 export class Run extends XmlComponent {
-    protected properties: RunProperties;
+    protected readonly properties: RunProperties;
 
     constructor() {
         super("w:r");

src/file/paragraph/run/sequential-identifier-instruction.ts

@@ -1,13 +1,9 @@
 // http://officeopenxml.com/WPfieldInstructions.php
+import { SpaceType } from "file/space-type";
 import { XmlAttributeComponent, XmlComponent } from "file/xml-components";
 
-enum SpaceType {
-    DEFAULT = "default",
-    PRESERVE = "preserve",
-}
-
-class TextAttributes extends XmlAttributeComponent<{ space: SpaceType }> {
-    protected xmlKeys = { space: "xml:space" };
+class TextAttributes extends XmlAttributeComponent<{ readonly space: SpaceType }> {
+    protected readonly xmlKeys = { space: "xml:space" };
 }
 
 export class SequentialIdentifierInstruction extends XmlComponent {

src/file/paragraph/run/style.ts

@@ -1,7 +1,7 @@
 import { XmlAttributeComponent, XmlComponent } from "file/xml-components";
 
-class StyleAttributes extends XmlAttributeComponent<{ val: string }> {
-    protected xmlKeys = { val: "w:val" };
+class StyleAttributes extends XmlAttributeComponent<{ readonly val: string }> {
+    protected readonly xmlKeys = { val: "w:val" };
 }
 
 export class Style extends XmlComponent {