More fun with colors

demo/colors.ts

@@ -1,34 +1,63 @@
 /**
  * This is a test file and a terminal color table program
  */
-import Ansi, { Ground } from '../src/common/ansi.ts';
+import Ansi, { AnsiColor, Ground } from '../src/common/ansi.ts';
 // ----------------------------------------------------------------------------
 // Display table of the 256 type color console escape codes
 // ----------------------------------------------------------------------------
+
+const addColor = (fore: number | string, back: number | string): string => {
+	let output = '';
+	output += (typeof fore === 'number') ? Ansi.color(fore) : fore;
+	output += (typeof back === 'number') ? Ansi.color(back) : back;
+
+	return output;
+};
+
+const padNum = (num: number): string =>
+	String(num).padStart(3, ' ').padEnd(5, ' ');
+
+const colorBlock = (
+	start: number,
+	end: number,
+	block: (i: number) => [string | number, string | number],
+): string => {
+	let output = '';
+
+	for (let i = start; i < end; i++) {
+		const [fg, bg] = block(i);
+
+		output += addColor(fg, bg);
+		output += padNum(i);
+		output += Ansi.ResetFormatting;
+	}
+	return output;
+};
+
 function print16colorTable(): void {
-	let colorTable = '';
+	const drawRow = (start: number): string => {
-
-	[30, 90].forEach((start) => {
-		let i = 0;
 		let end = start + 8;
-		for (i = start; i < end; i++) {
-			colorTable += Ansi.color(i);
-			colorTable += String(i).padStart(3, ' ').padEnd(4, ' ');
-			colorTable += Ansi.ResetFormatting;
-		}
 
-		colorTable += ' '.repeat(5);
+		let blocks = [
+			colorBlock(start, end, (i: number) => [i, AnsiColor.BgBlack]),
+			colorBlock(start, end, (i: number) => [i, AnsiColor.BgBrightWhite]),
+		];
 
 		start += 10;
 		end += 10;
-		for (i = start; i < end; i++) {
-			colorTable += Ansi.color(i);
-			colorTable += String(i).padStart(4, ' ').padEnd(5, ' ');
-			colorTable += Ansi.ResetFormatting;
-		}
 
-		colorTable += '\n';
+		blocks.push(colorBlock(start, end, (i: number) => [AnsiColor.FgBlack, i]));
-	});
+		blocks.push(
+			colorBlock(start, end, (i: number) => [AnsiColor.FgBrightWhite, i]),
+		);
+
+		return blocks.join(' '.repeat(5));
+	};
+
+	let colorTable = [
+		drawRow(30),
+		drawRow(90),
+	].join('\n');
 
 	colorTable += '\n';
 
@@ -53,22 +82,30 @@ function print256colorTable(): void {
 		const start = (n > 0) ? breaks[n - 1] + 1 : 0;
 		const end = line + 1;
 
-		let i = 0;
+		const blocks = [
-
+			colorBlock(
-		for (i = start; i < end; i++) {
+				start,
-			colorTable += Ansi.color256(i, Ground.Fore);
+				end,
-			colorTable += String(i).padStart(4, ' ').padEnd(5, ' ');
+				(i: number) => [Ansi.color256(i, Ground.Fore), AnsiColor.BgBlack],
-			colorTable += Ansi.ResetFormatting;
+			),
-		}
+			colorBlock(
-
+				start,
-		colorTable += ' '.repeat(5);
+				end,
-
+				(i: number) => [Ansi.color256(i, Ground.Fore), AnsiColor.BgBrightWhite],
-		for (i = start; i < end; i++) {
+			),
-			colorTable += Ansi.color256(i, Ground.Back);
+			colorBlock(
-			colorTable += String(i).padStart(4, ' ').padEnd(5, ' ');
+				start,
-			colorTable += Ansi.ResetFormatting;
+				end,
-		}
+				(i: number) => [AnsiColor.FgBlack, Ansi.color256(i, Ground.Back)],
+			),
+			colorBlock(
+				start,
+				end,
+				(i: number) => [AnsiColor.FgBrightWhite, Ansi.color256(i, Ground.Back)],
+			),
+		];
 
+		colorTable += blocks.join(' '.repeat(5));
 		colorTable += '\n';
 
 		if (doubleBreaks.includes(line)) {