Beginner Exercism • javascript

Diamond

Challenge Overview

The diamond kata takes as its input a letter, and outputs it in a diamond shape. Given a letter, it prints a diamond starting with 'A', with the supplied letter at the widest point.

Source: Exercism javascript/diamond

💡 View Solution

export class Diamond {
  makeDiamond(letter) {
    const alphabet = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
    const index = alphabet.indexOf(letter);
    const rows = [];

    for (let i = 0; i <= index; i++) {
      let row = '';
      const char = alphabet[i];
      const outerPadding = ' '.repeat(index - i);
      
      if (i === 0) {
        row = outerPadding + char + outerPadding;
      } else {
        const innerPadding = ' '.repeat(2 * i - 1);
        row = outerPadding + char + innerPadding + char + outerPadding;
      }
      rows.push(row);
    }

    for (let i = index - 1; i >= 0; i--) {
      rows.push(rows[i]);
    }

    return rows.join('\n') + '\n';
  }
}