2016 Update

Task/CSV-data-manipulation/JavaScript/csv-data-manipulation.js

@@ -0,0 +1,76 @@
+(function () {
+    'use strict';
+
+    // splitRegex :: Regex -> String -> [String]
+    function splitRegex(rgx, s) {
+        return s.split(rgx);
+    }
+
+    // lines :: String -> [String]
+    function lines(s) {
+        return s.split(/[\r\n]/);
+    }
+
+    // unlines :: [String] -> String
+    function unlines(xs) {
+        return xs.join('\n');
+    }
+
+    // macOS JavaScript for Automation version of readFile.
+    // Other JS contexts will need a different definition of this function,
+    // and some may have no access to the local file system at all.
+
+    // readFile :: FilePath -> maybe String
+    function readFile(strPath) {
+        var error = $(),
+            str = ObjC.unwrap(
+                $.NSString.stringWithContentsOfFileEncodingError(
+                    $(strPath)
+                    .stringByStandardizingPath,
+                    $.NSUTF8StringEncoding,
+                    error
+                )
+            );
+        return error.code ? error.localizedDescription : str;
+    }
+
+    // macOS JavaScript for Automation version of writeFile.
+    // Other JS contexts will need a different definition of this function,
+    // and some may have no access to the local file system at all.
+
+    // writeFile :: FilePath -> String -> IO ()
+    function writeFile(strPath, strText) {
+        $.NSString.alloc.initWithUTF8String(strText)
+            .writeToFileAtomicallyEncodingError(
+                $(strPath)
+                .stringByStandardizingPath, false,
+                $.NSUTF8StringEncoding, null
+            );
+    }
+
+    // EXAMPLE - appending a SUM column
+
+    var delimCSV = /,\s*/g;
+
+    var strSummed = unlines(
+        lines(readFile('~/csvSample.txt'))
+        .map(function (x, i) {
+            var xs = x ? splitRegex(delimCSV, x) : [];
+
+            return (xs.length ? xs.concat(
+                // 'SUM' appended to first line, others summed.
+                i > 0 ? xs.reduce(
+                    function (a, b) {
+                        return a + parseInt(b, 10);
+                    }, 0
+                ).toString() : 'SUM'
+            ) : []).join(',');
+        })
+    );
+
+    return (
+        writeFile('~/csvSampleSummed.txt', strSummed),
+        strSummed
+    );
+
+})();