Class KeyDetection

constructor

• new KeyDetection(): KeyDetection

  Returns KeyDetection

Static ReadonlymajorProfile

Static ReadonlyminorProfile

Staticdetect

• detect(
      notes: Note[],
      durations?: readonly number[],
      options?: KeyDetectionOptions,
  ): { confidence: number; key: string }[]

  Detects the most likely key based on an array of notes. Each note counts once, or by its duration when durations is given (as in the original Krumhansl-Schmuckler algorithm). Notes outside 12-TET count for the nearest 12-TET pitch class.

  Parameters

  • notes: Note[]

    The notes to analyse.

  • Optionaldurations: readonly number[]

    Optional duration of each note, in any unit (only proportions matter).

  • options: KeyDetectionOptions = {}

    profile: which key profile to correlate with (default Krumhansl-Kessler); modes: also read church modes.

  Returns { confidence: number; key: string }[]

  Array of possible keys sorted by confidence (Pearson correlation coefficient).

  • confidence: number

    Pearson correlation with the profile, -1 to 1.

  • key: string

    Key name with a capitalized mode: 'C Major', 'Eb Minor'; with modes, the first may be a church mode ('D Dorian').

  Throws

  RangeError if durations does not match notes in length, or holds a negative or non-finite value.

StaticdetectFromHistogram

• detectFromHistogram(
      weights: readonly number[],
      options?: KeyDetectionOptions,
  ): { confidence: number; key: string }[]

  Detects the most likely key from a pitch class histogram (index 0 = C, 1 = C#/Db, … 11 = B), e.g. total durations per pitch class accumulated over a piece.

  Parameters

  • weights: readonly number[]

    12 non-negative weights.

  • options: KeyDetectionOptions = {}

    profile: which key profile to correlate with (default Krumhansl-Kessler); modes: also read church modes.

  Returns { confidence: number; key: string }[]

  Array of possible keys sorted by confidence; empty when all weights are 0.

  • confidence: number

    Pearson correlation with the profile, -1 to 1.

  • key: string

    Key name with a capitalized mode: 'C Major', 'Eb Minor'; with modes, the first may be a church mode ('D Dorian').

  Throws

  RangeError if there are not 12 weights, or one is negative or non-finite.