remotion-dev/remotion · error · TypeError

"smoothness" must be a finite number, but got ${JSON.stringi

Error message

"smoothness" must be a finite number, but got ${JSON.stringify(params.smoothness)}

What it means

validateStarburstEffectParams() throws this TypeError when smoothness resolves to a non-finite value. smoothness is optional with a default of 0 (resolve() applies `?? 0`), so this fires only when the caller explicitly passes a non-number or non-finite number (NaN, Infinity). The subsequent range check (error 919) then enforces the [0,1] band.

Source

Thrown at packages/effects/src/starburst.ts:124

		throw new RangeError(`"rays" must be between 2 and 100, but got ${rays}`);
	}

	if (!Array.isArray(colors) || colors.length < 2) {
		throw new TypeError(
			`"colors" must be an array with at least 2 colors, but got ${JSON.stringify(colors)}`,
		);
	}

	const r = resolve(params);

	if (typeof r.rotation !== 'number' || !Number.isFinite(r.rotation)) {
		throw new TypeError(
			`"rotation" must be a finite number, but got ${JSON.stringify(params.rotation)}`,
		);
	}

	if (typeof r.smoothness !== 'number' || !Number.isFinite(r.smoothness)) {
		throw new TypeError(
			`"smoothness" must be a finite number, but got ${JSON.stringify(params.smoothness)}`,
		);
	}

	if (r.smoothness < 0 || r.smoothness > 1) {
		throw new RangeError(
			`"smoothness" must be between 0 and 1, but got ${r.smoothness}`,
		);
	}

	if (
		!Array.isArray(r.origin) ||
		r.origin.length !== 2 ||
		r.origin.some((coordinate) => {
			return typeof coordinate !== 'number' || !Number.isFinite(coordinate);
		})
	) {
		throw new TypeError('"origin" must be a [number, number] tuple');

View on GitHub (pinned to 78fe4bb3fd)

Solutions

  1. Pass a finite number in [0,1] for smoothness, or omit it for the default 0.
  2. If smoothness comes from user input, coerce (Number()) and check Number.isFinite before calling starburst().
  3. Annotate the source as number in TypeScript to catch non-numbers at compile time.
  4. Confirm the value is a 0–1 fraction, not a 0–100 percentage.

Example fix

// before
starburst({ rays: 12, colors: ['#ff0000','#00ff00'], smoothness: '50' });

// after
starburst({ rays: 12, colors: ['#ff0000','#00ff00'], smoothness: 0.5 });
Defensive patterns

Strategy: validation

Validate before calling

function resolveSmoothness(v: unknown): number {
  if (v === undefined) return 0;
  if (typeof v !== 'number' || !Number.isFinite(v)) {
    throw new TypeError(`"smoothness" must be a finite number, but got ${JSON.stringify(v)}`);
  }
  return v;
}

starburst({ rays, colors, smoothness: resolveSmoothness(input.smoothness) });

Type guard

function isOptionalFiniteNumber(v: unknown): v is number | undefined {
  return v === undefined || (typeof v === 'number' && Number.isFinite(v));
}

Try / catch

try {
  starburst({ rays, colors, smoothness });
} catch (err) {
  if (err instanceof TypeError && /"smoothness" must be a finite number/.test(err.message)) {
    // smoothness is optional — drop it and retry with the default of 0
    starburst({ rays, colors });
    return;
  }
  throw err;
}

Prevention

When it happens

Trigger: Calling starburst({ rays, colors, smoothness: NaN }), smoothness: Infinity, or smoothness: '0.5'. Omitting smoothness is safe (defaults to 0); only an explicitly bad value triggers this.

Common situations: Feeding smoothness from parsing/untrusted arithmetic that yields NaN; passing a string from a slider without coercion; copying a percentage (0–100) into a 0–1 field; animation producing NaN at a boundary.

Related errors

AI-assisted analysis of remotion-dev/remotion@78fe4bb3fd (2026-08-12). Data as JSON: /api/errors/8212953cc590199f. Report an issue: GitHub.