Just another update

Task/Align-columns/JavaScript/align-columns-2.js

@@ -0,0 +1,48 @@
+//break up each string by '$'. The assumption is that the user wants the trailing $.
+var data = [
+  "Given$a$text$file$of$many$lines,$where$fields$within$a$line$",
+  "are$delineated$by$a$single$'dollar'$character,$write$a$program",
+  "that$aligns$each$column$of$fields$by$ensuring$that$words$in$each$",
+  "column$are$separated$by$at$least$one$space.",
+  "Further,$allow$for$each$word$in$a$column$to$be$either$left$",
+  "justified,$right$justified,$or$center$justified$within$its$column."
+].map(function (str) { return str.split('$'); })
+
+//boilerplate: get longest array or string in array
+var getLongest = function (arr) {
+  return arr.reduce(function (acc, item) { return acc.length > item.length ? acc : item; }, 0);
+};
+
+//boilerplate: this function would normally be in a library like underscore, lodash, or ramda
+var zip = function (items, toInsert) {
+  toInsert = (toInsert === undefined) ? null : toInsert;
+  var longestItem = getLongest(items);
+  return longestItem.map(function (_unused, index) {
+    return items.map(function (item) {
+      return item[index] === undefined ? toInsert : item[index];
+    });
+  });
+};
+
+//here's the part that's not boilerplate
+var makeColumns = function (formatting, data) {
+  var zipData = zip(data, '');
+  var makeSpaces = function (num) { return new Array(num + 1).join(' '); };
+  var formattedCols = zipData.map(function (column) {
+    var maxLen = getLongest(column).length;//find the maximum word length
+    if (formatting === 'left') {
+      return column.map(function (word) { return word + makeSpaces(maxLen - word.length); });
+    } else if (formatting === 'right') {
+      return column.map(function (word) { return makeSpaces(maxLen - word.length) + word; });
+    } else {
+      return column.map(function (word) {
+        var spaces = maxLen - word.length,
+            first = ~~(spaces / 2),
+            last = spaces - first;
+        return makeSpaces(first) + word + makeSpaces(last);
+      });
+    }
+  });
+
+  return zip(formattedCols).map(function (row) { return row.join(' '); }).join('\n');
+};