src/Error/FormattedError.php
private static function highlightSourceAtLocation(Source $source, SourceLocation $location)
    {
        $line          = $location->line;
        $lineOffset    = $source->locationOffset->line - 1;
        $columnOffset  = self::getColumnOffset($source, $location);
        $contextLine   = $line + $lineOffset;
        $contextColumn = $location->column + $columnOffset;
        $prevLineNum   = (string) ($contextLine - 1);
        $lineNum       = (string) $contextLine;
        $nextLineNum   = (string) ($contextLine + 1);
        $padLen        = strlen($nextLineNum);
        $lines         = preg_split('/\r\n|[\n\r]/', $source->body);

        $lines[0] = self::whitespace($source->locationOffset->column - 1) . $lines[0];

        $outputLines = [
            sprintf('%s (%s:%s)', $source->name, $contextLine, $contextColumn),
            $line >= 2 ? (self::lpad($padLen, $prevLineNum) . ': ' . $lines[$line - 2]) : null,
            self::lpad($padLen, $lineNum) . ': ' . $lines[$line - 1],
            self::whitespace(2 + $padLen + $contextColumn - 1) . '^',
            $line < count($lines) ? self::lpad($padLen, $nextLineNum) . ': ' . $lines[$line] : null,
        ];

        return implode("\n", array_filter($outputLines));
    }
private static function highlightSourceAtLocation(Source $source, SourceLocation $location)
    {
        $line          = $location->line;
        $lineOffset    = $source->locationOffset->line - 1;
        $columnOffset  = self::getColumnOffset($source, $location);
        $contextLine   = $line + $lineOffset;
        $contextColumn = $location->column + $columnOffset;
        $prevLineNum   = (string) ($contextLine - 1);
        $lineNum       = (string) $contextLine;
        $nextLineNum   = (string) ($contextLine + 1);
        $padLen        = strlen($nextLineNum);
        $lines         = preg_split('/\r\n|[\n\r]/', $source->body);

        $lines[0] = self::whitespace($source->locationOffset->column - 1) . $lines[0];

        $outputLines = [
            sprintf('%s (%s:%s)', $source->name, $contextLine, $contextColumn),
            $line >= 2 ? (self::lpad($padLen, $prevLineNum) . ': ' . $lines[$line - 2]) : null,
            self::lpad($padLen, $lineNum) . ': ' . $lines[$line - 1],
            self::whitespace(2 + $padLen + $contextColumn - 1) . '^',
            $line < count($lines) ? self::lpad($padLen, $nextLineNum) . ': ' . $lines[$line] : null,
        ];

        return implode("\n", array_filter($outputLines));
    }
Render a helpful description of the location of the error in the GraphQL
Source document.

@return string