protected virtual JavaScriptWithSourceMap TransformWithHeader()

in src/React.Core/Babel.cs [217:244]

• 20 lines of code
• 4 McCabe index (conditional complexity)

		protected virtual JavaScriptWithSourceMap TransformWithHeader(
			string filename, 
			string contents, 
			string hash = null
		)
		{
			var result = TransformWithSourceMap(contents, filename);
			if (string.IsNullOrEmpty(hash))
			{
				hash = _fileCacheHash.CalculateHash(contents);
			}
			// Prepend header to generated code
			var header = GetFileHeader(hash, result.BabelVersion);
			result.Code = header + result.Code;
			result.Hash = hash;

			if (result.SourceMap != null && result.SourceMap.Mappings != null)
			{
				// Since we prepend a header to the code, the source map no longer matches up exactly
				// (it's off by the number of lines in the header). Fix this issue by adding five 
				// blank lines to the source map. This is kinda hacky but saves us having to load a
				// proper source map library. If this ever breaks, I'll replace it with actual proper
				// source map modification code (https://gist.github.com/Daniel15/4bdb15836bfd960c2956).
				result.SourceMap.Mappings = ";;;;;" + result.SourceMap.Mappings;
			}

			return result;
		}