Add "7" to Chords

You're organizing a jazz band, and in jazz music, many chords often have a "7" added to them (like "C7" or "G7"). However, some of the chords in your sheet music are missing the "7". Your task is to go through the list of chords and add a "7" to the end of each chord that doesn't already end with "7".

Instructions:

• Write a function named addSevenToChords that takes an array of chords as input.

• The function should return a new array where the number "7" is concatenated to the end of every chord that does not already end with "7".

• If a chord already ends with "7", it should remain unchanged.

Note: Only use the map, filter, or reduce methods, or a combination of these methods, to solve the problem. Do not use loops to iterate or perform the operation.

Example 1

Input: addSevenToChords(["E", "F#", "G7", "A#"]);
Output: ["E7", "F#7", "G7", "A#7"]

Example 2

Input: addSevenToChords(["Cmaj7", "D", "Em7", "F"]);
Output: ["Cmaj7", "D7", "Em7", "F7"]

Example 3

Input: addSevenToChords([]);
Output: []