Some example using TypeScript compiler API

ts-compiler.ts

import ts from 'typescript';
import { readFile, writeFile } from 'fs/promises';

const sourceText = await readFile('./input.ts', { encoding: 'utf8' });

const source = ts.createSourceFile('input.ts', sourceText, ts.ScriptTarget.Latest);

const newArticle = ts.factory.createObjectLiteralExpression(
  [
    ts.factory.createPropertyAssignment(
      ts.factory.createIdentifier('title'),
      ts.factory.createStringLiteral('New Article'),
    ),
    ts.factory.createPropertyAssignment(
      ts.factory.createIdentifier('url'),
      ts.factory.createStringLiteral('New Article'),
    ),
  ],
  true,
);

const transformer: ts.TransformerFactory<ts.SourceFile> = (context) => {
  const visitNode = (node: ts.Node): ts.Node => {
    if (ts.isVariableDeclaration(node) && node.name.getText(source) === 'articles') {
      const updatedArray = context.factory.updateArrayLiteralExpression(
        node.initializer as ts.ArrayLiteralExpression,
        [
          newArticle,
          ...node?.initializer?.elements,
        ],
      );

      return context.factory.updateVariableDeclaration(node, node.name, node.exclamationToken, node.type, updatedArray);
    }

    return ts.visitEachChild(node, visitNode, context);
  }

  return (sourceFile) => ts.visitNode(sourceFile, visitNode);
}

const transformedSourceFile = ts.transform(source, [transformer]);

const printer = ts.createPrinter();

const updated = printer.printNode(
  ts.EmitHint.Unspecified,
  transformedSourceFile.transformed[0],
  ts.createSourceFile("./output.ts", "", ts.ScriptTarget.Latest)
);

await writeFile('./output.ts', updated);