Method truncateSync

lib/internal/vfs/file_handle.js:678–705

* Truncates the file synchronously. * @param {number} [len] The new length

(len = 0)

   * @param {number} [len] The new length
   */
  truncateSync(len = 0) {
    this.#checkClosed('ftruncate');
    this.#checkWritable();

    if (len < this.#size) {
      // Zero out truncated region to avoid stale data
      this.#content.fill(0, len, this.#size);
      this.#size = len;
    } else if (len > this.#size) {
      if (len > this.#content.length) {
        const newContent = Buffer.alloc(len);
        this.#content.copy(newContent, 0, 0, this.#size);
        this.#content = newContent;
      } else {
        // Buffer has enough capacity, just zero-fill the extension
        this.#content.fill(0, this.#size, len);
      }
      this.#size = len;
    }

    // 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;
    }
  }

  /**
   * Truncates the file.