Handle slicing of links (chalk#32)

dspasojevic · Mar 22, 2021 · 9cd0ec1 · 9cd0ec1
1 parent 1d1eb94
commit 9cd0ec1
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Showing 2 changed files with 97 additions and 13 deletions.
diff --git a/index.js b/index.js
@@ -8,31 +8,41 @@ const ESCAPES = [
 	'\u009B'
 ];
 
-const wrapAnsi = code => `${ESCAPES[0]}[${code}m`;
+const ANSI_ESCAPE_BELL = '\u0007';
+const ANSI_CSI = '[';
+const ANSI_OSC = ']';
+const ANSI_SGR_TERMINATOR = 'm';
+const ANSI_SEP = ';';
+const ANSI_ESCAPE_LINK = `${ANSI_OSC}8${ANSI_SEP}${ANSI_SEP}`;
+const ANSI_LINK_TEXT_TERMINATOR = `${ESCAPES[0]}${ANSI_ESCAPE_LINK}${ANSI_ESCAPE_BELL}`;
+
+const wrapAnsi = code => `${ESCAPES[0]}${ANSI_CSI}${code}${ANSI_SGR_TERMINATOR}`;
+const wrapAnsiHyperlinkUri = uri => `${ESCAPES[0]}${ANSI_ESCAPE_LINK}${uri}${ANSI_ESCAPE_BELL}`;
 
 const checkAnsi = (ansiCodes, isEscapes, endAnsiCode) => {
 	let output = [];
 	ansiCodes = [...ansiCodes];
 
 	for (let ansiCode of ansiCodes) {
-		const ansiCodeOrigin = ansiCode;
-		if (ansiCode.includes(';')) {
+		const ansiCodeOriginal = ansiCode;
+
+		if (ansiCode && ansiCode.includes(';')) {
 			ansiCode = ansiCode.split(';')[0][0] + '0';
 		}
 
 		const item = ansiStyles.codes.get(Number.parseInt(ansiCode, 10));
 		if (item) {
 			const indexEscape = ansiCodes.indexOf(item.toString());
 			if (indexEscape === -1) {
-				output.push(wrapAnsi(isEscapes ? item : ansiCodeOrigin));
+				output.push(wrapAnsi(isEscapes ? item : ansiCodeOriginal));
 			} else {
 				ansiCodes.splice(indexEscape, 1);
 			}
 		} else if (isEscapes) {
 			output.push(wrapAnsi(0));
 			break;
 		} else {
-			output.push(wrapAnsi(ansiCodeOrigin));
+			output.push(wrapAnsi(ansiCodeOriginal));
 		}
 	}
 
@@ -53,17 +63,41 @@ module.exports = (string, begin, end) => {
 	const ansiCodes = [];
 
 	let stringEnd = typeof end === 'number' ? end : characters.length;
+
+	// Track the state of the three types of escape code (regular, link uri, link text)
 	let isInsideEscape = false;
+	let isInsideLinkUriEscape = false;
+	let isInsideLinkTextEscape = false;
+
 	let ansiCode;
+
+	// How many visible characters have been added to the output. Characters added while isInsideEscape is true
+	// do not count towards this total.
 	let visible = 0;
 	let output = '';
+	let escapeUri;
+
+	// Has the URI been added, so we need to terminate the link if we get to the end without terminating somehow.
+	let needToTerminateLink = false;
+
+	// Whether we are processing the link text.
+	let processingLinkText = false;
 
 	for (const [index, character] of characters.entries()) {
 		let leftEscape = false;
 
 		if (ESCAPES.includes(character)) {
-			const code = /\d[^m]*/.exec(string.slice(index, index + 18));
-			ansiCode = code && code.length > 0 ? code[0] : undefined;
+			const remainingString = string.slice(index);
+			const {groups} = new RegExp(`(?:\\${ANSI_CSI}(?<code>\\d[^m]*)|\\${ANSI_ESCAPE_LINK}(?<uri>[^${ANSI_ESCAPE_BELL}]*)${ANSI_ESCAPE_BELL})`).exec(remainingString) || {groups: {}};
+			if (groups.code !== undefined) {
+				ansiCode = groups.code;
+			} else if (groups.uri !== undefined && !processingLinkText) {
+				escapeUri = groups.uri.length === 0 ? null : groups.uri;
+				isInsideLinkUriEscape = true;
+			} else if (remainingString.startsWith(ANSI_LINK_TEXT_TERMINATOR)) {
+				isInsideLinkTextEscape = true;
+				processingLinkText = false;
+			}
 
 			if (visible < stringEnd) {
 				isInsideEscape = true;
@@ -72,9 +106,27 @@ module.exports = (string, begin, end) => {
 					ansiCodes.push(ansiCode);
 				}
 			}
-		} else if (isInsideEscape && character === 'm') {
-			isInsideEscape = false;
-			leftEscape = true;
+		}
+
+		if (isInsideEscape) {
+			if (isInsideLinkUriEscape) {
+				if (character === ANSI_ESCAPE_BELL) {
+					isInsideEscape = false;
+					isInsideLinkUriEscape = false;
+					leftEscape = true;
+					processingLinkText = true;
+				}
+			} else if (isInsideLinkTextEscape) {
+				if (character === ANSI_ESCAPE_BELL) {
+					isInsideEscape = false;
+					isInsideLinkTextEscape = false;
+					leftEscape = true;
+					needToTerminateLink = false;
+				}
+			} else if (character === ANSI_SGR_TERMINATOR) {
+				isInsideEscape = false;
+				leftEscape = true;
+			}
 		}
 
 		if (!isInsideEscape && !leftEscape) {
@@ -91,10 +143,24 @@ module.exports = (string, begin, end) => {
 
 		if (visible > begin && visible <= stringEnd) {
 			output += character;
-		} else if (visible === begin && !isInsideEscape && ansiCode !== undefined) {
-			output = checkAnsi(ansiCodes);
+		} else if (visible === begin && !isInsideEscape) {
+			output = '';
+			if (ansiCode !== undefined) {
+				output += checkAnsi(ansiCodes);
+			}
+
+			if (escapeUri !== undefined) {
+				output += wrapAnsiHyperlinkUri(escapeUri);
+				escapeUri = undefined;
+				needToTerminateLink = true;
+			}
 		} else if (visible >= stringEnd) {
 			output += checkAnsi(ansiCodes, true, ansiCode);
+
+			if (needToTerminateLink) {
+				output += ANSI_LINK_TEXT_TERMINATOR;
+			}
+
 			break;
 		}
 	}

diff --git a/test.js b/test.js
@@ -98,7 +98,25 @@ test('does not lose fullwidth characters', t => {
 	t.is(sliceAnsi('古古test', 0), '古古test');
 });
 
-test.failing('slice links', t => {
+test('slice links', t => {
 	const link = '\u001B]8;;https://google.com\u0007Google\u001B]8;;\u0007';
 	t.is(sliceAnsi(link, 0, 6), link);
 });
+
+test('slice links - shortening', t => {
+	const link = '\u001B]8;;https://google.com\u0007Google\u001B]8;;\u0007';
+	const expected = '\u001B]8;;https://google.com\u0007Goog\u001B]8;;\u0007';
+	t.is(JSON.stringify(sliceAnsi(link, 0, 4)), JSON.stringify(expected));
+});
+
+test('slice links - going over link', t => {
+	const link = '\u001B]8;;https://google.com\u0007Google\u001B]8;;\u0007 and some more text';
+	const expected = '\u001B]8;;https://google.com\u0007Google\u001B]8;;\u0007 and s';
+	t.is(JSON.stringify(sliceAnsi(link, 0, 12)), JSON.stringify(expected));
+});
+
+test('slice links mid text', t => {
+	const link = 'some entry text \u001B]8;;https://google.com\u0007Google\u001B]8;;\u0007 and some more text';
+	const expected = 'some entry text \u001B]8;;https://google.com\u0007Google\u001B]8;;\u0007 an';
+	t.is(JSON.stringify(sliceAnsi(link, 0, 25)), JSON.stringify(expected));
+});