Resolve "Diamond kata TS"

Closes #115 (closed)

diamond-ts/src/Diamond.spec.ts

+const letters = [
+  'A',
+  'B',
+  'C',
+  'D',
+  'E',
+  'F',
+  'G',
+  'H',
+  'I',
+  'J',
+  'K',
+  'L',
+  'M',
+  'N',
+  'O',
+  'P',
+  'Q',
+  'R',
+  'S',
+  'T',
+  'U',
+  'V',
+  'W',
+  'X',
+  'Y',
+  'Z',
+];
+
+const getDiamond = (letter: string) => {
+  if (letter === 'A') {
+    return getPyramid(letter);
+  }
+  const topPyramid = getPyramid(letter);
+  const bottomPyramid = topPyramid.slice(0, -1).reverse();
+  return [...topPyramid, ...bottomPyramid];
+};
+
+const getSpace = (numberOfSpace: number) => ' '.repeat(numberOfSpace);
+
+const getLine = (index: number, letterIndex: number) => {
+  const currentLetter = letters[index];
+  const aroundSpace = letterIndex - index;
+  if (currentLetter === 'A') {
+    return getSpace(aroundSpace) + currentLetter + getSpace(aroundSpace);
+  }
+  const insideSpace = index * 2 - 1;
+  return getSpace(aroundSpace) + currentLetter + getSpace(insideSpace) + currentLetter + getSpace(aroundSpace);
+};
+
+const getPyramid = (givenLetter: string) => {
+  const letterIndex = letters.indexOf(givenLetter);
+  const pyramid = [];
+  for (let index = 0; index <= letterIndex; index++) {
+    const line = getLine(index, letterIndex);
+    pyramid.push(line);
+  }
+  return pyramid;
+};
+
+describe('Diamond', () => {
+  it('Should be A for A', () => {
+    expect(getDiamond('A')).toStrictEqual(['A']);
+  });
+
+  it('Should get B diamond', () => {
+    expect(getDiamond('B')).toStrictEqual([' A ', 'B B', ' A ']);
+  });
+
+  it('Should get C diamond', () => {
+    expect(getDiamond('C')).toStrictEqual(['  A  ', ' B B ', 'C   C', ' B B ', '  A  ']);
+  });
+
+  it('Should get A pyramid', () => {
+    expect(getPyramid('A')).toStrictEqual(['A']);
+  });
+
+  it('Should get C pyramid', () => {
+    expect(getPyramid('C')).toStrictEqual(['  A  ', ' B B ', 'C   C']);
+  });
+});