Function createTwoFilesPatch

src/patch/create.ts:527–567

(
  oldFileName: string,
  newFileName: string,
  oldStr: string,
  newStr: string,
  oldHeader?: string,
  newHeader?: string,
  options?: CreatePatchOptionsAbortable | CreatePatchOptionsNonabortable | CreatePatchCallbackNonabortable
)

  options?: CreatePatchOptionsNonabortable
): string
export function createTwoFilesPatch(
  oldFileName: string,
  newFileName: string,
  oldStr: string,
  newStr: string,
  oldHeader?: string,
  newHeader?: string,
  options?: CreatePatchOptionsAbortable | CreatePatchOptionsNonabortable | CreatePatchCallbackNonabortable
): string | undefined {
  if (typeof options === 'function') {
    options = {callback: options};
  }

  if (!options?.callback) {
    const patchObj = structuredPatch(oldFileName, newFileName, oldStr, newStr, oldHeader, newHeader, options as any);
    if (!patchObj) {
      return;
    }
    return formatPatch(patchObj, options?.headerOptions);
  } else {
    const {callback} = options;
    structuredPatch(
      oldFileName,
      newFileName,
      oldStr,
      newStr,
      oldHeader,
      newHeader,
      {
        ...options,
        callback: patchObj => {
          if (!patchObj) {
            (callback as CreatePatchCallbackAbortable)(undefined);
          } else {
            callback(formatPatch(patchObj, options.headerOptions));
          }
        }
      }
    );
  }
}

/**
 * creates a unified diff patch.