@tonaljs/progression

Convert chord list to roman numerals analysis chord and reverse

Usage

ES6:

import { Progression } from "tonal";

node:

const { Progression } = require("tonal");

API

Progression.fromRomanNumerals(keyTonic: string, chordProgression: string[]) => string[]

Given a tonic and a chord progression expressed in roman numeral analysis chords, returns the progression expressed in leadsheet chords.

Progression.fromRomanNumerals("C", ["IMaj7", "IIm7", "V7"]);
// => ["CMaj7", "Dm7", "G7"]

Progression.toRomanNumerals(keyTonic: string, chordProgression: string[]) => string[]

The opposite of fromRomanNumerals. Given a tonic and a chord progression expressed in leadsheet chords, returns the progression using roman numeral analysis chords.

Progression.toRomanNumerals("C", ["CMaj7", "Dm7", "G7"]);
// => "IMaj7", "IIm7", "V7"]

Resources

• Roman numeral analysis
• Leadsheet chord symbols