Re-name templater to patcher

src/patcher/paragraph-token-replacer.ts

@@ -0,0 +1,64 @@
+import { Element } from "xml-js";
+
+import { createTextElementContents } from "./util";
+import { IRenderedParagraphNode } from "./run-renderer";
+
+enum ReplaceMode {
+    START,
+    MIDDLE,
+    END,
+}
+
+export const replaceTokenInParagraphElement = ({
+    paragraphElement,
+    renderedParagraph,
+    originalText,
+    replacementText,
+}: {
+    readonly paragraphElement: Element;
+    readonly renderedParagraph: IRenderedParagraphNode;
+    readonly originalText: string;
+    readonly replacementText: string;
+}): Element => {
+    const startIndex = renderedParagraph.text.indexOf(originalText);
+    const endIndex = startIndex + originalText.length - 1;
+
+    let replaceMode = ReplaceMode.START;
+
+    for (const run of renderedParagraph.runs) {
+        for (const { text, index, start, end } of run.parts) {
+            switch (replaceMode) {
+                case ReplaceMode.START:
+                    if (startIndex >= start) {
+                        const partToReplace = run.text.substring(Math.max(startIndex, start), Math.min(endIndex, end) + 1);
+                        // We use a token to split the text if the replacement is within the same run
+                        // If not, we just add text to the middle of the run later
+                        const firstPart = text.replace(partToReplace, replacementText);
+                        patchTextElement(paragraphElement.elements![run.index].elements![index], firstPart);
+                        replaceMode = ReplaceMode.MIDDLE;
+                        continue;
+                    }
+                    break;
+                case ReplaceMode.MIDDLE:
+                    if (endIndex <= end) {
+                        const lastPart = text.substring(endIndex - start + 1);
+                        patchTextElement(paragraphElement.elements![run.index].elements![index], lastPart);
+                        replaceMode = ReplaceMode.END;
+                    } else {
+                        patchTextElement(paragraphElement.elements![run.index].elements![index], "");
+                    }
+                    break;
+                default:
+            }
+        }
+    }
+
+    return paragraphElement;
+};
+
+const patchTextElement = (element: Element, text: string): Element => {
+    // eslint-disable-next-line functional/immutable-data
+    element.elements = createTextElementContents(text);
+
+    return element;
+};