allow pdf_options.margin to be passed as a CSS-like string

index.js

@@ -16,6 +16,7 @@ const readFile = require('./util/read-file');
 const getHtml = require('./util/get-html');
 const writePdf = require('./util/write-pdf');
 const config = require('./util/config');
+const { getMarginObject } = require('./util/helpers');
 
 // --
 // Configure CLI Arguments
@@ -97,6 +98,11 @@ async function main(args, config) {
 		config[key] = jsonArgs.includes(argKey) ? JSON.parse(argValue) : argValue;
 	}
 
+	// sanitize the margin in pdf_options
+	if (typeof config.pdf_options.margin === 'string') {
+		config.pdf_options.margin = getMarginObject(config.pdf_options.margin);
+	}
+
 	const highlightStylesheet = path.resolve(
 		__dirname,
 		'node_modules',

test.js

@@ -6,7 +6,7 @@ const config = require('./util/config');
 const getHtml = require('./util/get-html');
 const getMarkedWithHighlighter = require('./util/get-marked-with-highlighter');
 const getPdfFilePath = require('./util/get-pdf-file-path');
-const { getDir } = require('./util/helpers');
+const { getDir, getMarginObject } = require('./util/helpers');
 const readFile = require('./util/read-file');
 const waitForLocalhost = require('./util/wait-for-localhost');
 
@@ -59,6 +59,17 @@ test('getDir should get the directory the given file is in', t => {
 	t.is('/var/foo', getDir(filePath));
 });
 
+test('getMarginObject should be able to handle all valid CSS margin inputs', t => {
+	t.deepEqual(getMarginObject('1em'), { top: '1em', right: '1em', bottom: '1em', left: '1em' });
+	t.deepEqual(getMarginObject('1px 2px'), { top: '1px', right: '2px', bottom: '1px', left: '2px' });
+	t.deepEqual(getMarginObject('1mm 2mm 3mm'), { top: '1mm', right: '2mm', bottom: '3mm', left: '2mm' });
+	t.deepEqual(getMarginObject('1in 2in 3in 4in'), { top: '1in', right: '2in', bottom: '3in', left: '4in' });
+	t.is(getMarginObject(null), null);
+	t.throws(() => getMarginObject({}));
+	t.throws(() => getMarginObject(0));
+	t.throws(() => getMarginObject('1em 2em 3em 4em 5em'));
+});
+
 // --
 // read-file
 

util/helpers.js

@@ -7,3 +7,35 @@ const { parse, resolve } = require('path');
  * file.
  */
 module.exports.getDir = filePath => resolve(parse(filePath).dir);
+
+/**
+ * Get a margin object from a string.
+ * @param {String} margin A CSS-like margin setting
+ * @returns object with keys 'top', 'right', 'bottom', 'left'
+ */
+module.exports.getMarginObject = margin => {
+	if (margin === null) {
+		return null;
+	}
+
+	if (typeof margin === 'string') {
+		const margins = margin.split(' ');
+		const [top, right, bottom, left] = margins;
+
+		switch (margins.length) {
+			case 1:
+				return { top, right: top, bottom: top, left: top };
+			case 2:
+				return { top, right, bottom: top, left: right };
+			case 3:
+				return { top, right, bottom, left: right };
+			case 4:
+				return { top, right, bottom, left };
+
+			default:
+				break; // will throw the error below
+		}
+	}
+
+	throw new Error(`invalid margin input: ${margin}`);
+};