Class Interval

constructor

• new Interval(cents: number): Interval

  Create an interval from a value in cents. Prefer fromCents() or fromRatio() for clarity.

  Parameters

  • cents: number

    Size in cents (1200 = octave); negative for a descending interval.

  Returns Interval

cents

ratio

• get ratio(): number

  The interval as a decimal frequency ratio (e.g. 1.5 for a perfect fifth).

  Returns number

semitones

• get semitones(): number

  The interval in semitones (cents / 100). May be fractional for microtonal intervals.

  Returns number

add

• add(other: Interval): Interval

  Add two intervals (stack them).

  Parameters

  • other: Interval

  Returns Interval

divide

• divide(factor: number): Interval

  Divide the interval by a numeric factor.

  Parameters

  • factor: number

  Returns Interval

equals

• equals(other: Interval, toleranceCents?: number): boolean

  Compare two intervals within a tolerance.

  Parameters

  • other: Interval

    The interval to compare against.

  • toleranceCents: number = 1

    Maximum allowed difference in cents (default: 1¢).

  Returns boolean

inOctave

• inOctave(): Interval

  Reduce the interval to a single octave (0–1200 cents). Useful for pitch-class equivalence and scale analysis.

  Returns Interval

multiply

• multiply(factor: number): Interval

  Scale the interval by a numeric factor.

  Parameters

  • factor: number

  Returns Interval

negate

• negate(): Interval

  Return the descending (negative) form of this interval. Useful for voice leading and downward transposition.

  Returns Interval

subtract

• subtract(other: Interval): Interval

  Subtract an interval (remove it from this one).

  Parameters

  • other: Interval

  Returns Interval

StaticfromCents

• fromCents(cents: number): Interval

  Create an interval from a value in cents.

  Parameters

  • cents: number

  Returns Interval

StaticfromRatio

• fromRatio(ratio: Ratio): Interval

  Create an interval from a frequency ratio.

  Parameters

  • ratio: Ratio

    Integer fraction [numerator, denominator] or decimal (e.g. [3,2] or 1.5 for a perfect fifth).

  Returns Interval

  Throws

  if the ratio is zero, negative, or not finite.