Update handling of out-of-bounds indices

Planeshifter · Planeshifter · commit 8249695f2c65 · 2021-10-11T15:45:48.000-04:00
diff --git a/lib/node_modules/@stdlib/string/prev-grapheme-cluster-break/lib/main.js b/lib/node_modules/@stdlib/string/prev-grapheme-cluster-break/lib/main.js
@@ -82,12 +82,13 @@ function prevGraphemeClusterBreak( str, fromIndex ) {
 	} else {
 		idx = len - 1;
 	}
-	if ( idx < 0 ) {
-		idx += len;
-	}
-	if ( len === 0 || idx >= len ) {
+	if ( len === 0 || idx <= 0 ) {
 		return -1;
 	}
+	if ( idx >= len ) {
+		idx = len - 1;
+	}
+
 	// Initialize caches for storing grapheme break and emoji properties:
 	breaks = [];
 	emoji = [];
diff --git a/lib/node_modules/@stdlib/string/prev-grapheme-cluster-break/test/test.js b/lib/node_modules/@stdlib/string/prev-grapheme-cluster-break/test/test.js
@@ -121,20 +121,25 @@ tape( 'the function throws an error if the second argument is not an integer', f
 	}
 });
 
-tape( 'the function returns -1 if the provided position is greater than or equal to the string length', function test( t ) {
+tape( 'the function returns uses the default position if the provided position is greater than or equal to the string length', function test( t ) {
+	var expected;
 	var out;
 
 	out = prevGraphemeClusterBreak( 'last man standing', 17 );
-	t.strictEqual( out, -1, 'returns expected value' );
+	expected = prevGraphemeClusterBreak( 'last man standing' );
+	t.strictEqual( out, expected, 'returns expected value' );
 
 	out = prevGraphemeClusterBreak( 'presidential election', 22 );
-	t.strictEqual( out, -1, 'returns expected value' );
+	expected = prevGraphemeClusterBreak( 'presidential election' );
+	t.strictEqual( out, expected, 'returns expected value' );
 
 	out = prevGraphemeClusterBreak( 'अनुच्छेद', 10 );
-	t.strictEqual( out, -1, 'returns expected value' );
+	expected = prevGraphemeClusterBreak( 'अनुच्छेद' );
+	t.strictEqual( out, expected, 'returns expected value' );
 
 	out = prevGraphemeClusterBreak( '🌷', 2 );
-	t.strictEqual( out, -1, 'returns expected value' );
+	expected = prevGraphemeClusterBreak( '🌷' );
+	t.strictEqual( out, expected, 'returns expected value' );
 
 	t.end();
 });
@@ -187,26 +192,26 @@ tape( 'the function returns the previous grapheme break position in a specified
 	t.end();
 });
 
-tape( 'the function supports negative integers for second argument', function test( t ) {
+tape( 'the function returns zero when the second argument is a negative integer (equivalent to clamping the second argument to zero)', function test( t ) {
 	var out;
 
 	out = prevGraphemeClusterBreak( 'last man standing', -13 );
-	t.strictEqual( out, 3, 'returns expected value' );
+	t.strictEqual( out, -1, 'returns expected value' );
 
 	out = prevGraphemeClusterBreak( 'presidential election', -13 );
-	t.strictEqual( out, 7, 'returns expected value' );
+	t.strictEqual( out, -1, 'returns expected value' );
 
 	out = prevGraphemeClusterBreak( 'अनुच्छेद', -6 );
-	t.strictEqual( out, 0, 'returns expected value' );
+	t.strictEqual( out, -1, 'returns expected value' );
 
 	out = prevGraphemeClusterBreak( 'अनुच्छेद', -5 );
-	t.strictEqual( out, 2, 'returns expected value' );
+	t.strictEqual( out, -1, 'returns expected value' );
 
 	out = prevGraphemeClusterBreak( 'अनुच्छेद', -2 );
-	t.strictEqual( out, 4, 'returns expected value' );
+	t.strictEqual( out, -1, 'returns expected value' );
 
 	out = prevGraphemeClusterBreak( '🌷🐷', -2 );
-	t.strictEqual( out, 1, 'returns expected value' );
+	t.strictEqual( out, -1, 'returns expected value' );
 
 	t.end();
 });
