nwjs/nw.js · error · TypeError

Type of '{type}' is not supported

Error message

Type of '{type}' is not supported

What it means

Clipboard.prototype.set only supports the 'text' type. After defaulting type to 'text' when undefined, any other value (e.g., 'png', 'html', 'file') throws a TypeError before the native Set call. This is a deliberate limitation of the nw.js clipboard binding, not a generic clipboard API.

Source

Thrown at src/api/clipboard/clipboard.js:33

// PLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNES
// S FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS
//  OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WH
// ETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
//  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

var clipboardInstance = null;

function Clipboard() {
  nw.allocateObject(this, {});
}
require('util').inherits(Clipboard, exports.Base);

Clipboard.prototype.set = function(data, type) {
  if (typeof type == 'undefined')
    type = 'text';

  if (type != 'text')
    throw new TypeError("Type of '" + type + "' is not supported");

  nw.callObjectMethod(this, 'Set', [ data, type ]);
}

Clipboard.prototype.get = function(type) {
  if (typeof type == 'undefined')
    type = 'text';

  if (type != 'text')
    throw new TypeError('Only support getting plain text from Clipboard');

  var result = nw.callObjectMethodSync(this, 'Get', [ type ]);
  if (type == 'text')
    return String(result);
}

Clipboard.prototype.clear = function() {
  nw.callObjectMethod(this, 'Clear', [ ]);

View on GitHub (pinned to e15da848e9)

Solutions

1. Call set(data) or set(data, 'text') — plain text is the only supported type.
2. If you need rich content (HTML/image), write the data to a temp file and put the path/text on the clipboard instead.
3. Double-check there is no capitalization typo in the type argument.

Example fix

// before
nw.Clipboard.get().set('<b>hi</b>', 'html'); // throws

// after
nw.Clipboard.get().set('<b>hi</b>', 'text'); // stored as literal text

function setText(data, type) {
  type = (typeof type === 'undefined') ? 'text' : type;
  if (type !== 'text') throw new Error('Unsupported clipboard type: ' + type);
  nw.Clipboard.get().set(data, 'text');
}

function isTextType(t) { return t === undefined || t === 'text'; }

try { nw.Clipboard.get().set(data, type); }
catch (e) {
  if (e instanceof TypeError && /not supported/.test(e.message)) {
    nw.Clipboard.get().set(String(data), 'text'); // fall back to text
  } else { throw e; }
}

When it happens

Trigger: Calling nw.Clipboard.get().set(data, 'html'), .set(data, 'png'), or .set(data, 'rtf'). Passing a typo like .set(data, 'Text') (capital T) also fails because the check is case-sensitive against the literal 'text'.

Common situations: Developers assume nw.js mirrors Electron/Chromium's clipboard with types like 'image/png' or 'html'. Migration from Electron where clipboard.writeText/writeImage were separate calls. Case-sensitivity mistakes ('Text' vs 'text').

Related errors

• Only support getting plain text from Clipboard
• Invaild parameter, need Shortcut object.
• Menu.append() requires a valid MenuItem
• 'submenu' must be a valid Menu
• 'click' must be a valid Function

AI-assisted analysis of nwjs/nw.js@e15da848e9 (2026-08-13). Data as JSON: /api/errors/3864de09153bf9a9. Report an issue: GitHub.