```ts
export function foldDigraphs(text: string, table: Array<[string, string]>): string {
  let folded = text;
  for (const [pattern, output] of table) {
    if (pattern === "") {
      throw new Error("empty pattern");
    }
    const regex = new RegExp(pattern, "g");
    folded = folded.replace(regex, () => output);
  }
  return folded;
}
```