Fix weird null issue (#19)

schani · sindresorhus · commit e41217cd3a08 · 2018-10-17T01:39:54.000+07:00
diff --git a/index.js b/index.js
@@ -18,7 +18,7 @@ module.exports = (str, begin, end) => {
 	end = typeof end === 'number' ? end : arr.length;
 
 	let insideEscape = false;
-	let escapeCode;
+	let escapeCode = null;
 	let visible = 0;
 	let output = '';
 
@@ -44,10 +44,10 @@ module.exports = (str, begin, end) => {
 
 		if (visible > begin && visible <= end) {
 			output += x;
-		} else if (visible === begin && !insideEscape && escapeCode !== undefined && escapeCode !== END_CODE) {
+		} else if (visible === begin && !insideEscape && escapeCode !== null && escapeCode !== END_CODE) {
 			output += wrapAnsi(escapeCode);
 		} else if (visible >= end) {
-			if (escapeCode !== undefined) {
+			if (escapeCode !== null) {
 				output += wrapAnsi(ansiStyles.codes.get(parseInt(escapeCode, 10)) || END_CODE);
 			}
 			break;
diff --git a/test.js b/test.js
@@ -57,3 +57,9 @@ test.failing('can slice a normal character before a colored character', t => {
 test.failing('can slice a normal character after a colored character', t => {
 	t.is(m('\u001B[31ma\u001B[39mb', 1, 2), 'b');
 });
+
+test('weird null issue', t => {
+	const s = '\u001B[1mautotune.flipCoin("easy as") ? 🎂 : 🍰 \u001B[33m★\u001B[39m\u001B[22m';
+	const result = m(s, 38);
+	t.is(result.search('null'), -1);
+});
