Method writeFileSync

lib/internal/vfs/file_handle.js:609–640

* Writes data to the file synchronously. * Replaces content in 'w' mode, appends in 'a' mode. * @param {Buffer|string} data The data to write * @param {object} [options] Options

(data, options)

   * @param {object} [options] Options
   */
  writeFileSync(data, options) {
    this.#checkClosed('write');
    this.#checkWritable();

    const buffer = typeof data === 'string' ? Buffer.from(data, options?.encoding) : data;

    // In append mode, append to existing content
    if (this.#isAppend()) {
      const neededSize = this.#size + buffer.length;
      if (neededSize > this.#content.length) {
        const newCapacity = MathMax(neededSize, this.#content.length * 2);
        const newContent = Buffer.alloc(newCapacity);
        this.#content.copy(newContent, 0, 0, this.#size);
        this.#content = newContent;
      }
      buffer.copy(this.#content, this.#size);
      this.#size = neededSize;
    } else {
      this.#content = Buffer.from(buffer);
      this.#size = buffer.length;
    }

    // Update the entry's content, mtime, and ctime
    if (this.#entry) {
      const now = DateNow();
      this.#entry.content = this.#content.subarray(0, this.#size);
      this.#entry.mtime = now;
      this.#entry.ctime = now;
    }

    this.position = this.#size;
  }

  /**
   * Writes data to the file (replacing content).