Add width option (#70)

Co-authored-by: Sindre Sorhus <sindresorhus@gmail.com>

Author: Caesarovich

example.js

@@ -61,3 +61,7 @@ const title = 'Beautiful title';
 console.log('\n\n' + boxen('This box has a nice title', {title}) + '\n');
 
 console.log('\n\n' + boxen('This box has a centered title', {title, titleAlignment: 'center'}) + '\n');
+
+console.log('\n\n' + boxen('This box has fixed width of 20', {width: 20}) + '\n');
+
+console.log('\n\n' + boxen('This box has fixed width of 50', {width: 50}) + '\n');

index.d.ts

@@ -176,6 +176,23 @@ export interface Options {
 	```
 	*/
 	readonly titleAlignment?: 'left' | 'right' | 'center';
+
+	/**
+	Set a fixed width for the box.
+
+	**Note*: This disables terminal overflow handling and may cause the box to look broken if the user's terminal is not wide enough.
+
+	@example
+	```
+	import boxen from 'boxen';
+
+	console.log(boxen('foo bar', {width: 15}));
+	// ┌─────────────┐
+	// │foo bar      │
+	// └─────────────┘
+	```
+	*/
+	readonly width?: number;
 }
 
 /**

index.js

@@ -221,6 +221,66 @@ const boxContent = (content, contentWidth, options) => {
 	return top + LINE_SEPARATOR + middle + LINE_SEPARATOR + bottom;
 };
 
+const determineDimensions = (text, options) => {
+	const widthOverride = options.width !== undefined;
+	const columns = terminalColumns();
+	const maxWidth = columns - options.margin.left - options.margin.right - BORDERS_WIDTH;
+
+	// If width is provided, make sure it's not below 1
+	if (options.width) {
+		options.width = Math.max(1, options.width - BORDERS_WIDTH);
+	}
+
+	const widest = widestLine(wrapAnsi(text, columns - BORDERS_WIDTH, {hard: true, trim: false})) + options.padding.left + options.padding.right;
+
+	// If title and width are provided, title adheres to fixed width
+	if (options.title && widthOverride) {
+		options.title = options.title.slice(0, Math.max(0, options.width - 2));
+		if (options.title) {
+			options.title = ` ${options.title} `;
+		}
+	} else if (options.title) {
+		options.title = options.title.slice(0, Math.max(0, maxWidth - 2));
+
+		// Recheck if title isn't empty now
+		if (options.title) {
+			options.title = ` ${options.title} `;
+			// If the title is larger than content, box adheres to title width
+			if (stringWidth(options.title) > widest) {
+				options.width = stringWidth(options.title);
+			}
+		}
+	}
+
+	// If fixed width is provided, use it or content width as reference
+	options.width = options.width ? options.width : widest;
+
+	if (!widthOverride) {
+		if ((options.margin.left && options.margin.right) && options.width > maxWidth) {
+			// Let's assume we have margins: left = 3, right = 5, in total = 8
+			const spaceForMargins = columns - options.width - BORDERS_WIDTH;
+			// Let's assume we have space = 4
+			const multiplier = spaceForMargins / (options.margin.left + options.margin.right);
+			// Here: multiplier = 4/8 = 0.5
+			options.margin.left = Math.max(0, Math.floor(options.margin.left * multiplier));
+			options.margin.right = Math.max(0, Math.floor(options.margin.right * multiplier));
+			// Left: 3 * 0.5 = 1.5 -> 1
+			// Right: 6 * 0.5 = 3
+		}
+
+		// Re-cap width considering the margins after shrinking
+		options.width = Math.min(options.width, columns - BORDERS_WIDTH - options.margin.left - options.margin.right);
+	}
+
+	// Prevent padding overflow
+	if (options.width - (options.padding.left + options.padding.right) <= 0) {
+		options.padding.left = 0;
+		options.padding.right = 0;
+	}
+
+	return options;
+};
+
 const isHex = color => color.match(/^#(?:[0-f]{3}){1,2}$/i);
 const isColorValid = color => typeof color === 'string' && ((chalk[color]) || isHex(color));
 const getColorFn = color => isHex(color) ? chalk.hex(color) : chalk[color];
@@ -253,39 +313,11 @@ export default function boxen(text, options) {
 	options.padding = getObject(options.padding);
 	options.margin = getObject(options.margin);
 
-	const columns = terminalColumns();
-
-	let contentWidth = widestLine(wrapAnsi(text, columns - BORDERS_WIDTH, {hard: true, trim: false})) + options.padding.left + options.padding.right;
-
-	// This prevents the title bar to exceed the console's width
-	options.title = options.title && options.title.slice(0, columns - 4 - options.margin.left - options.margin.right);
-
-	if (options.title) {
-		options.title = ` ${options.title} `;
-		// Make the box larger to fit a larger title
-		if (stringWidth(options.title) > contentWidth) {
-			contentWidth = stringWidth(options.title);
-		}
-	}
-
-	if ((options.margin.left && options.margin.right) && contentWidth + BORDERS_WIDTH + options.margin.left + options.margin.right > columns) {
-		// Let's assume we have margins: left = 3, right = 5, in total = 8
-		const spaceForMargins = columns - contentWidth - BORDERS_WIDTH;
-		// Let's assume we have space = 4
-		const multiplier = spaceForMargins / (options.margin.left + options.margin.right);
-		// Here: multiplier = 4/8 = 0.5
-		options.margin.left = Math.max(0, Math.floor(options.margin.left * multiplier));
-		options.margin.right = Math.max(0, Math.floor(options.margin.right * multiplier));
-		// Left: 3 * 0.5 = 1.5 -> 1
-		// Right: 6 * 0.5 = 3
-	}
-
-	// Prevent content from exceeding the console's width
-	contentWidth = Math.min(contentWidth, columns - BORDERS_WIDTH - options.margin.left - options.margin.right);
+	options = determineDimensions(text, options);
 
-	text = makeContentText(text, options.padding, contentWidth, options.textAlignment);
+	text = makeContentText(text, options.padding, options.width, options.textAlignment);
 
-	return boxContent(text, contentWidth, options);
+	return boxContent(text, options.width, options);
 }
 
 export const _borderStyles = cliBoxes;

index.test-d.ts

@@ -35,3 +35,4 @@ expectType<string>(boxen('unicorns', {float: 'center'}));
 expectType<string>(boxen('unicorns', {backgroundColor: 'green'}));
 expectType<string>(boxen('unicorns', {backgroundColor: '#ff0000'}));
 expectType<string>(boxen('unicorns', {textAlignment: 'right'}));
+expectType<string>(boxen('unicorns', {width: 20}));

readme.md

@@ -192,6 +192,14 @@ Values:
 */
 ```
 
+##### width
+
+Type: `number`
+
+Set a fixed width for the box.
+
+*Note:* This disables terminal overflow handling and may cause the box to look broken if the user's terminal is not wide enough.
+
 ##### padding
 
 Type: `number | object`\

tests/snapshots/tests/title-option.js.md

@@ -43,3 +43,25 @@ Generated by [AVA](https://avajs.dev).
     `┌ very long title ┐␊
     │foo              │␊
     └─────────────────┘`
+
+## title + width option
+
+> Snapshot 1
+
+    `┌─┐␊
+    │f│␊
+    │o│␊
+    │o│␊
+    └─┘`
+
+> Snapshot 2
+
+    `┌ v ┐␊
+    │foo│␊
+    └───┘`
+
+> Snapshot 3
+
+    `┌ very long title ─┐␊
+    │foo               │␊
+    └──────────────────┘`

tests/snapshots/tests/title-option.js.snap

@@ -0,0 +1,48 @@
+# Snapshot report for `tests/width-option.js`
+
+The actual snapshot is saved in `width-option.js.snap`.
+
+Generated by [AVA](https://avajs.dev).
+
+## width option works
+
+> Snapshot 1
+
+    `┌──────────────────┐␊
+    │foo               │␊
+    └──────────────────┘`
+
+> Snapshot 2
+
+    `┌────────┐␊
+    │foo bar │␊
+    │foo bar │␊
+    └────────┘`
+
+## width option with padding + margin
+
+> Snapshot 1
+
+    `␊
+    ␊
+          ┌──────────────────┐␊
+          │                  │␊
+          │   foo            │␊
+          │                  │␊
+          └──────────────────┘␊
+    ␊
+    `
+
+## width option with big padding
+
+> Snapshot 1
+
+    `┌────┐␊
+    │    │␊
+    │    │␊
+    │    │␊
+    │foo │␊
+    │    │␊
+    │    │␊
+    │    │␊
+    └────┘`

tests/snapshots/tests/width-option.js.md

@@ -43,3 +43,28 @@ test('long title expands box', t => {
 
 	t.snapshot(box);
 });
+
+test('title + width option', t => {
+	// Not enough space, no title
+	t.snapshot(
+		boxen('foo', {
+			title: 'very long title',
+			width: 3,
+		}),
+	);
+
+	// Space for only one character
+	t.snapshot(
+		boxen('foo', {
+			title: 'very long title',
+			width: 5,
+		}),
+	);
+
+	t.snapshot(
+		boxen('foo', {
+			title: 'very long title',
+			width: 20,
+		}),
+	);
+});