All the rules for defining which notes to play for a given scale are added in a JSON file named scales.json within a folder named json. Let's take a look at the first few lines in the scales.json file:
{ "Major": [ 0, 2, 4, 5, 7, 9, 11 ], "Minor": [ 0, 2, 3, 5, 7, 8, 10 ], "Harmonic minor": [ 0, 2, 3, 5, 7, 8, 11 ], "Melodic minor": [ 0, 2, 3, 5, 7, 9, 11 ], "Major blues": [ 0, 2, 3, 4, 7, 9 ], "Minor blues": [ 0, 3, 5, 6, 7, 10 ],...}
Recall that a scale is a set of notes played sequentially. The first note of the scale is called its root or key. So if you play a scale starting at say the note B, you are playing the scale in the key of B.
Let's take the fourth item in the key-value pairs. The key is named "Melodic ...