feat: Add BOM character option (#187)

bin/json2csv.js

@@ -28,6 +28,7 @@ program
   .option('-L, --ldjson', 'Treat the input as Line-Delimited JSON.')
   .option('-p, --pretty', 'Use only when printing to console. Logs output in pretty tables.')
   .option('-a, --include-empty-rows', 'Includes empty rows in the resulting CSV output.')
+  .option('-b, --with-bom', 'Includes BOM character at the beginning of the csv.')
   .parse(process.argv);
 
 function getFields(callback) {
@@ -112,7 +113,8 @@ getFields(function (err, fields) {
       quotes: program.quote,
       defaultValue: program.defaultValue,
       flatten: program.flatten,
-      includeEmptyRows: program.includeEmptyRows
+      includeEmptyRows: program.includeEmptyRows,
+      withBOM: program.withBOM
     };
 
     if (program.delimiter) {

lib/json2csv.js

@@ -27,6 +27,7 @@ var flatten = require('flat');
  * @property {String[]} [unwindPath] - similar to MongoDB's $unwind, Deconstructs an array field from the input JSON to output a row for each element
  * @property {Boolean} [excelStrings] - converts string data into normalized Excel style data
  * @property {Boolean} [includeEmptyRows=false] - includes empty rows
+ * @property {Boolean} [withBOM=false] - includes BOM character at the beginning of the csv
  */
 
 /**
@@ -138,6 +139,9 @@ function checkParams(params) {
   //#check include empty rows, defaults to false
   params.includeEmptyRows = params.includeEmptyRows || false;
 
+  //#check with BOM, defaults to false
+  params.withBOM = params.withBOM || false;
+
   //#check unwindPath, defaults to empty array
   params.unwindPath = params.unwindPath || [];
 
@@ -282,13 +286,17 @@ function createColumnContent(params, str) {
       }
     }
   });
+  // Add BOM character if required
+  if (params.withBOM) {
+    str = '\ufeff ' + str;
+  }
 
   return str;
 }
 
 /**
  * Performs the unwind recursively in specified sequence
- * 
+ *
  * @param {Array} originalData The params.data value. Original array of JSON objects
  * @param {String[]} unwindPaths The params.unwindPath value. Unwind strings to be used to deconstruct array
  * @returns {Array} Array of objects containing all rows after unwind of chosen paths
@@ -314,7 +322,7 @@ function createDataRows(originalData, unwindPaths) {
 
 /**
  * Performs the unwind logic if necessary to convert single JSON document into multiple rows
- * 
+ *
  * @param {Array} inputRows Array contaning single or multiple rows to unwind
  * @param {String} unwindPath Single path to do unwind
  * @returns {Array} Array of rows processed

test/fixtures/csv/withBOM.csv

@@ -0,0 +1,5 @@
+"carModel","price","color","transmission"
+"Audi",0,"blue",
+"BMW",15000,"red","manual"
+"Mercedes",20000,"yellow",
+"Citroën",30000,"green",

test/fixtures/json/specialCharacters.json

@@ -0,0 +1,23 @@
+[
+  {
+    "carModel": "Audi",
+    "price": 0,
+    "color": "blue"
+  },
+  {
+    "carModel": "BMW",
+    "price": 15000,
+    "color": "red",
+    "transmission": "manual"
+  },
+  {
+    "carModel": "Mercedes",
+    "price": 20000,
+    "color": "yellow"
+  },
+  {
+    "carModel": "Citroën",
+    "price": 30000,
+    "color": "green"
+  }
+]

test/helpers/load-fixtures.js

@@ -29,7 +29,8 @@ var fixtures = [
   'emptyRowNotIncluded',
   'emptyRowDefaultValues',
   'unwind',
-  'unwind2'
+  'unwind2',
+  'withBOM',
 ];
 
 /*eslint-disable no-console*/

test/index.js

@@ -16,6 +16,7 @@ var jsonEmptyRow = require('./fixtures/json/emptyRow');
 var jsonUnwind = require('./fixtures/json/unwind');
 var jsonUnwind2 = require('./fixtures/json/unwind2');
 var jsonNewLine = require('./fixtures/json/newLine');
+var jsonSpecialCharacters = require('./fixtures/json/specialCharacters');
 var csvFixtures = {};
 
 async.parallel(loadFixtures(csvFixtures), function (err) {
@@ -620,7 +621,6 @@ async.parallel(loadFixtures(csvFixtures), function (err) {
     })
   });
 
-
   test('should unwind twice an array into multiple rows', function(t) {
     json2csv({
       data: jsonUnwind2,
@@ -665,4 +665,15 @@ async.parallel(loadFixtures(csvFixtures), function (err) {
       t.end();
     });
   });
+
+  test('should add BOM character', function (t) {
+    var csv = json2csv({
+      data: jsonSpecialCharacters,
+      withBOM: true
+    });
+    // Compare csv length to check if the BOM character and the space after are present
+    t.equal(csv.length, csvFixtures.default.length + 2);
+    t.equal(csv.length, csvFixtures.withBOM.length);
+    t.end();
+  });
 });