better empty file checkig and error msgs

lib/index.js

@@ -16,29 +16,23 @@ var formatters = {
     return JSON.stringify(file)
   },
   csv: function (file) {
-    if (!_.isArray(file)) {
-      reporters.notListError('csv')
-    }
+    file = formattingPreflight(file, 'csv')
     try {
       return dsv.csv.format(file)
     } catch (err) {
       reporters.parseError('csv')
     }
   },
   tsv: function (file) {
-    if (!_.isArray(file)) {
-      reporters.notListError('tsv')
-    }
+    file = formattingPreflight(file, 'tsv')
     try {
       return dsv.tsv.format(file)
     } catch (err) {
       reporters.parseError('tsv')
     }
   },
   psv: function (file) {
-    if (!_.isArray(file)) {
-      reporters.notListError('psv')
-    }
+    file = formattingPreflight(file, 'psv')
     try {
       return dsv.dsv('|').format(file)
     } catch (err) {
@@ -95,7 +89,7 @@ reporters.parseError = function (format) {
 }
 
 reporters.notListError = function (format) {
-  throw new Error(chalk.red('[indian-ocean] You passed in an object but converting to ' + chalk.bold(format) + ' requires a list of objects.') + chalk.cyan('\nIf you would like to write a one-row csv, put your object in a list like so: ' + chalk.bold('[data]') + '\n'))
+  throw new Error(chalk.red('[indian-ocean] You passed in an object but converting to ' + chalk.bold(format) + ' requires a list of objects.') + chalk.cyan('\nIf you would like to write a one-row csv, put your object in a list like so: `' + chalk.bold('[data]') + '`\n'))
 }
 
 /**
@@ -300,6 +294,16 @@ helpers.matches = function (fileName, matcher) {
   }
 }
 
+// Some shared data integrity checks for formatters
+function formattingPreflight (file, format) {
+  if (file === '') {
+    return []
+  } else if (!_.isArray(file)) {
+    reporters.notListError(format)
+  }
+  return file
+}
+
 // Our `readData` fns can take either a delimiter to parse a file, or a full blown parser
 // Determine what they passed in with this handy function
 function getDelimiterOrParser (delimiterOrParser) {
@@ -931,7 +935,7 @@ writers.writeData = function (outPath, data, opts_, cb) {
     cb = opts_
   }
   if (!data) {
-    reporters.warn('You didn\'t pass any data to write for file: ' + chalk.bold(outPath))
+    reporters.warn('You didn\'t pass any data to write for file: ' + chalk.bold(outPath) + ' Writing out an empty file...')
   }
 
   if (_.isObject(opts_) && opts_.makeDirectories) {
@@ -968,8 +972,8 @@ writers.writeData = function (outPath, data, opts_, cb) {
  *
  */
 writers.writeDataSync = function (outPath, data, opts_) {
-  if (!data) {
-    reporters.warn('You didn\'t pass any data to write for file: ' + chalk.bold(outPath))
+  if (_.isEmpty(data)) {
+    reporters.warn('You didn\'t pass any data to write for file: ' + chalk.bold(outPath) + ' Writing out an empty file...')
   }
   if (opts_ && opts_.makeDirectories) {
     helpers.makeDirectoriesSync(outPath)