perf(manipulation): #807 - Optimise getTextFromTextChanges performance

Refs:
- #806

packages/ts-morph/src/manipulation/formatting/getTextFromFormattingEdits.ts

@@ -2,22 +2,21 @@ import { ts } from "@ts-morph/common";
 import { SourceFile, TextChange } from "../../compiler";
 
 export function getTextFromTextChanges(sourceFile: SourceFile, textChanges: ReadonlyArray<TextChange | ts.TextChange>) {
-    // reverse the order
-    const reversedFormattingEdits = textChanges.map((edit, index) => ({ edit: toWrappedTextChange(edit), index })).sort((a, b) => {
-        const aStart = a.edit.getSpan().getStart();
-        const bStart = b.edit.getSpan().getStart();
-        const difference = bStart - aStart;
-        if (difference === 0)
-            return a.index < b.index ? 1 : -1;
-        return difference > 0 ? 1 : -1;
-    });
-
-    let text = sourceFile.getFullText();
-    for (const { edit } of reversedFormattingEdits) {
+    const text = sourceFile.getFullText();
+    let start = 0;
+    let end = 0;
+    const editResult: Array<string> = [];
+    for (const textChange  of textChanges) {
+        const edit = toWrappedTextChange(textChange);
         const span = edit.getSpan();
-        text = text.slice(0, span.getStart()) + edit.getNewText() + text.slice(span.getEnd());
+        end = span.getStart();
+        const beforeEdit = text.slice(start, end);
+        start = span.getEnd();
+        editResult.push(beforeEdit);
+        editResult.push(edit.getNewText());
     }
-    return text;
+    editResult.push(text.slice(start));
+    return editResult.join('');
 
     function toWrappedTextChange(change: TextChange | ts.TextChange) {
         if (change instanceof TextChange)