lovell/sharp · error · Error

Expected noise to be an object

Error message

Expected noise to be an object

What it means

Thrown when inputOptions.create.noise is defined but is not an object. The noise generator requires a descriptor with at least a type field (and optionally mean/sigma), so passing a primitive (number, string, array) is rejected before any field is read. The guard is `!is.object(inputOptions.create.noise)`.

Solutions

1. Wrap the noise spec in an object with a type field: noise: { type: 'gaussian', mean: 128, sigma: 30 }.
2. Ensure mean and sigma (if provided) are numbers in range 0-10000.
3. Confirm channels is 1-4 (a separate check inside the noise branch will enforce 1-4).

Example fix

// before
sharp({ create: { width: 100, height: 100, channels: 3, noise: 'gaussian' } })

// after
sharp({ create: { width: 100, height: 100, channels: 3, noise: { type: 'gaussian', mean: 128, sigma: 30 } } })

function noiseCreate(opts) {
  if (typeof opts.noise !== 'object' || opts.noise === null) {
    throw new Error('create.noise must be an object e.g. { type: "gaussian", mean, sigma }');
  }
  return sharp({ create: opts });
}

function isNoiseObject(v) {
  return v !== null && typeof v === 'object' && !Array.isArray(v);
}

When it happens

Trigger: sharp({ create: { width, height, channels, noise: 'gaussian' } }) — a string instead of an object. noise: 5 or noise: ['gaussian']. Mistakenly passing the type directly instead of wrapping it.

Common situations: Misreading the API and assuming noise takes a string type. Copying an example that used the old/imagined shorthand. Auto-generating options from a config where noise ended up as a scalar.

Related errors

• Expected valid noise or background to create a new input…
• Only gaussian noise is supported at the moment
• Expected a valid string to create an image with text.
• Expected create.height
• Expected valid width, height and channels to create a new…

AI-assisted analysis of lovell/sharp@56676c6918 (2026-08-13). Data as JSON: /api/errors/96eb70b8aecee8c1. Report an issue: GitHub.

Appendix: source

Thrown at lib/input.mjs:353

      ) {
        inputDescriptor.createWidth = inputOptions.create.width;
        inputDescriptor.createHeight = inputOptions.create.height;
        inputDescriptor.createChannels = inputOptions.create.channels;
        inputDescriptor.createPageHeight = 0;
        if (is.defined(inputOptions.create.pageHeight)) {
          if (is.integer(inputOptions.create.pageHeight) && inputOptions.create.pageHeight > 0 && inputOptions.create.pageHeight <= inputOptions.create.height) {
            if (inputOptions.create.height % inputOptions.create.pageHeight !== 0) {
              throw new Error(`Expected create.height ${inputOptions.create.height} to be a multiple of create.pageHeight ${inputOptions.create.pageHeight}`);
            }
            inputDescriptor.createPageHeight = inputOptions.create.pageHeight;
          } else {
            throw is.invalidParameterError('create.pageHeight', 'positive integer', inputOptions.create.pageHeight);
          }
        }
        // Noise
        if (is.defined(inputOptions.create.noise)) {
          if (!is.object(inputOptions.create.noise)) {
            throw new Error('Expected noise to be an object');
          }
          if (inputOptions.create.noise.type !== 'gaussian') {
            throw new Error('Only gaussian noise is supported at the moment');
          }
          inputDescriptor.createNoiseType = inputOptions.create.noise.type;
          if (!is.inRange(inputOptions.create.channels, 1, 4)) {
            throw is.invalidParameterError('create.channels', 'number between 1 and 4', inputOptions.create.channels);
          }
          inputDescriptor.createNoiseMean = 128;
          if (is.defined(inputOptions.create.noise.mean)) {
            if (is.number(inputOptions.create.noise.mean) && is.inRange(inputOptions.create.noise.mean, 0, 10000)) {
              inputDescriptor.createNoiseMean = inputOptions.create.noise.mean;
            } else {
              throw is.invalidParameterError('create.noise.mean', 'number between 0 and 10000', inputOptions.create.noise.mean);
            }
          }
          inputDescriptor.createNoiseSigma = 30;
          if (is.defined(inputOptions.create.noise.sigma)) {

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