Only skip first n lines in the first chunk and don't take the first l…

…ine as header (mholt#1045)

papaparse.js

@@ -511,6 +511,11 @@ License: MIT
 		this.parseChunk = function(chunk, isFakeChunk)
 		{
 			// First chunk pre-processing
+			const skipFirstNLines = parseInt(this._config.skipFirstNLines) || 0;
+			if (this.isFirstChunk && skipFirstNLines > 0) {
+				const splitChunk = chunk.split('\n');
+				chunk = [...splitChunk.slice(skipFirstNLines)].join('\n');
+			}
 			if (this.isFirstChunk && isFunction(this._config.beforeFirstChunk))
 			{
 				var modifiedChunk = this._config.beforeFirstChunk(chunk);
@@ -522,22 +527,6 @@ License: MIT
 
 			// Rejoin the line we likely just split in two by chunking the file
 			var aggregate = this._partialLine + chunk;
-			this._pendingSkip = parseInt(this._config.skipFirstNLines) || 0;
-			this._skipHeader = 0;
-			if (this._config.header) {
-				this._skipHeader++;
-			}
-			if (this._pendingSkip > 0) {
-				var splitChunk = aggregate.split('\n');
-				var currentChunkLength = splitChunk.length;
-				if (currentChunkLength <= this._pendingSkip) {
-					aggregate = this._partialLine;
-				}
-				else{
-					aggregate = this._partialLine + [...splitChunk.slice(0, this._skipHeader), ...splitChunk.slice(this._skipHeader + this._pendingSkip)].join('\n');
-				}
-				this._pendingSkip -= currentChunkLength;
-			}
 			this._partialLine = '';
 			var results = this._handle.parse(aggregate, this._baseIndex, !this._finished);
 

tests/test-cases.js

@@ -1585,11 +1585,11 @@ var PARSE_TESTS = [
 		}
 	},
 	{
-		description: "Skip First N number of lines , with header and 3 rows",
-		input: 'a,b,c,d\n1,2,3,4\n4,5,6,7',
+		description: "Skip First N number of lines , with header and 2 rows",
+		input: 'to-be-ignored\na,b,c,d\n1,2,3,4',
 		config: { header: true, skipFirstNLines: 1 },
 		expected: {
-			data: [{a: '4', b: '5', c: '6', d: '7'}],
+			data: [{a: '1', b: '2', c: '3', d: '4'}],
 			errors: []
 		}
 	},