build: strip YAML frontmatter from breaking changes in changelog

PR-URL: #6100
Closes: stdlib-js/metr-issue-tracker#53
Co-authored-by: Athan Reines <[email protected]>
Reviewed-by: Athan Reines <[email protected]>

Author: Planeshifter

lib/node_modules/@stdlib/_tools/changelog/generate/lib/breaking_changes.js

@@ -1,4 +1,3 @@
-
 /**
 * @license Apache-2.0
 *
@@ -24,6 +23,7 @@
 var filter = require( '@stdlib/array/base/filter' );
 var trim = require( '@stdlib/string/trim' );
 var map = require( '@stdlib/utils/map' );
+var reEOL = require( '@stdlib/regexp/eol' );
 var collectField = require( './collect_field.js' );
 var sectionStart = require( './section_start.js' );
 var sectionEnd = require( './section_end.js' );
@@ -33,10 +33,51 @@ var heading = require( './heading.js' );
 // VARIABLES //
 
 var STDLIB_GITHUB_URL = 'https://github.com/stdlib-js/stdlib/commit';
+var RE_YAML_DELIMITER = /^\s*---\s*$/;
 
 
 // FUNCTIONS //
 
+/**
+* Processes commit message text by removing YAML blocks and squashing multiple empty lines into a single empty line.
+*
+* @private
+* @param {Array<string>} lines - text lines to process
+* @returns {Array<string>} processed commit message lines
+*/
+function stripYamlBlocks( lines ) {
+	var previousLineEmpty;
+	var inYaml;
+	var out;
+	var i;
+
+	previousLineEmpty = false;
+	inYaml = false;
+	out = [];
+	for ( i = 0; i < lines.length; i++ ) {
+		// Check for YAML delimiter (---) with optional whitespace:
+		if ( RE_YAML_DELIMITER.test( lines[ i ] ) ) {
+			inYaml = !inYaml; // Toggle YAML block state
+			continue;
+		}
+		// Only include lines that are not part of YAML blocks:
+		if ( inYaml ) {
+			continue;
+		}
+		if ( trim( lines[ i ] ) === '' ) {
+			// Only add an empty line if the previous line wasn't empty:
+			if ( !previousLineEmpty && out.length > 0 ) {
+				previousLineEmpty = true;
+				out.push( '' );
+			}
+		} else {
+			previousLineEmpty = false;
+			out.push( lines[ i ] ); // Preserve original line formatting
+		}
+	}
+	return out;
+}
+
 /**
 * Formats a breaking change.
 *
@@ -54,13 +95,26 @@ var STDLIB_GITHUB_URL = 'https://github.com/stdlib-js/stdlib/commit';
 * // returns '-   [`abcdef1`](https://github.com/stdlib-js/stdlib/commit/abcdef1234567890): beep'
 */
 function formatBreakingChange( note ) {
-	var parts = note.text.split( '\n' );
-	var hash = trim( note.hash );
-	var out = '-   [`'+hash.substring( 0, 7 )+'`]('+STDLIB_GITHUB_URL+'/'+hash+'): '+parts[ 0 ];
-	if ( parts.length > 1 ) {
-		out +='\n\n';
-		out += '    -   ';
-		out += parts.slice( 1 ).join( '\n        ' );
+	var contentLines;
+	var textLines;
+	var firstLine;
+	var restLines;
+	var hash;
+	var out;
+
+	textLines = note.text.split( reEOL.REGEXP );
+	contentLines = stripYamlBlocks( textLines );
+
+	// If we have content, first element is the first line:
+	firstLine = contentLines[ 0 ] || '';
+	restLines = contentLines.slice( 1 );
+	hash = trim( note.hash );
+
+	// Construct output string:
+	out = '-   [`' + hash.substring( 0, 7 ) + '`](' + STDLIB_GITHUB_URL + '/' + hash + '): ' + firstLine;
+	if ( restLines.length > 0 ) {
+		out += '\n\n';
+		out += '    -   ' + restLines.join( '\n        ' );
 		out += '\n';
 	}
 	return out;
@@ -88,18 +142,18 @@ function isBreakingChange( note ) {
 * @returns {string} list of breaking changes
 */
 function breakingChanges( commits ) {
-	var breakingChanges;
+	var changes;
 	var notes;
 	var out;
 
 	notes = collectField( commits, 'notes' );
-	breakingChanges = filter( notes, isBreakingChange );
-	if ( breakingChanges.length === 0 ) {
+	changes = filter( notes, isBreakingChange );
+	if ( changes.length === 0 ) {
 		return '';
 	}
 	out = sectionStart( 'breaking-changes' );
 	out += heading( 'BREAKING CHANGES', 3 );
-	out += map( breakingChanges, formatBreakingChange ).join( '\n' );
+	out += map( changes, formatBreakingChange ).join( '\n' );
 	out += sectionEnd( 'breaking-changes' );
 	return out;
 }