feat: Parameter unwindPath for multiple fields (#174) (#183)

* Add unwind multiple times as array

* Change small details as requested

.gitignore

@@ -7,3 +7,4 @@ published
 *.log
 dist
 _docpress
+.vscode

README.md

@@ -65,7 +65,7 @@ try {
   - `eol` - String, it gets added to each row of data. Defaults to `` if not specified.
   - `newLine` - String, overrides the default OS line ending (i.e. `\n` on Unix and `\r\n` on Windows).
   - `flatten` - Boolean, flattens nested JSON using [flat]. Defaults to `false`.
-  - `unwindPath` - String, creates multiple rows from a single JSON document similar to MongoDB's $unwind
+  - `unwindPath` - Array of Strings, creates multiple rows from a single JSON document similar to MongoDB's $unwind
   - `excelStrings` - Boolean, converts string data into normalized Excel style data.
   - `includeEmptyRows` - Boolean, includes empty rows. Defaults to `false`.
   - `preserveNewLinesInValues` - Boolean, preserve \r and \n in values. Defaults to `false`.
@@ -317,6 +317,77 @@ The content of the "file.csv" should be
 "Porsche",30000,"aqua"
 ```
 
+### Example 8
+
+You can also unwind arrays multiple times or with nested objects.
+
+```javascript
+var json2csv = require('json2csv');
+var fs = require('fs');
+var fields = ['carModel', 'price', 'items.name', 'items.color', 'items.items.position', 'items.items.color'];
+var myCars = [
+  {
+    "carModel": "BMW",
+    "price": 15000,
+    "items": [
+      {
+        "name": "airbag",
+        "color": "white"
+      }, {
+        "name": "dashboard",
+        "color": "black"
+      }
+    ]
+  }, {
+    "carModel": "Porsche",
+    "price": 30000,
+    "items": [
+      {
+        "name": "airbag",
+        "items": [
+          {
+            "position": "left",
+            "color": "white"
+          }, {
+            "position": "right",
+            "color": "gray"
+          }
+        ]
+      }, {
+        "name": "dashboard",
+        "items": [
+          {
+            "position": "left",
+            "color": "gray"
+          }, {
+            "position": "right",
+            "color": "black"
+          }
+        ]
+      }
+    ]
+  }
+];
+var csv = json2csv({ data: myCars, fields: fields, unwindPath: ['items', 'items.items'] });
+
+fs.writeFile('file.csv', csv, function(err) {
+  if (err) throw err;
+  console.log('file saved');
+});
+```
+
+The content of the "file.csv" should be
+
+```
+"carModel","price","items.name","items.color","items.items.position","items.items.color"
+"BMW",15000,"airbag","white",,
+"BMW",15000,"dashboard","black",,
+"Porsche",30000,"airbag",,"left","white"
+"Porsche",30000,"airbag",,"right","gray"
+"Porsche",30000,"dashboard",,"left","gray"
+"Porsche",30000,"dashboard",,"right","black"
+```
+
 ## Command Line Interface
 
 `json2csv` can also be called from the command line if installed with `-g`.
@@ -338,6 +409,7 @@ Usage: json2csv [options]
     -q, --quote [value]          Specify an alternate quote value.
     -n, --no-header              Disable the column name header
     -F, --flatten                Flatten nested objects
+    -u, --unwindPath <paths>     Creates multiple rows from a single JSON document similar to MongoDB unwind.
     -L, --ldjson                 Treat the input as Line-Delimited JSON.
     -p, --pretty                 Use only when printing to console. Logs output in pretty tables.
     -a, --include-empty-rows     Includes empty rows in the resulting CSV output.

bin/json2csv.js

@@ -24,6 +24,7 @@ program
   .option('-q, --quote [value]', 'Specify an alternate quote value.')
   .option('-n, --no-header', 'Disable the column name header')
   .option('-F, --flatten', 'Flatten nested objects')
+  .option('-u, --unwindPath <paths>', 'Creates multiple rows from a single JSON document similar to MongoDB unwind.')
   .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.')
@@ -126,6 +127,10 @@ getFields(function (err, fields) {
       opts.newLine = program.newLine;
     }
 
+    if (program.unwindPath) {
+      opts.unwindPath = program.fields.split(',');
+    }
+
     var csv = json2csv(opts);
 
     if (program.output) {

lib/json2csv.js

@@ -24,7 +24,7 @@ var flatten = require('flat');
  * @property {String} [eol=''] - it gets added to each row of data
  * @property {String} [newLine] - overrides the default OS line ending (\n on Unix \r\n on Windows)
  * @property {Boolean} [flatten=false] - flattens nested JSON using flat (https://www.npmjs.com/package/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 {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
  */
@@ -137,6 +137,14 @@ function checkParams(params) {
 
   //#check include empty rows, defaults to false
   params.includeEmptyRows = params.includeEmptyRows || false;
+
+  //#check unwindPath, defaults to empty array
+  params.unwindPath = params.unwindPath || [];
+
+  // if unwindPath is not in array [{}], then just create 1 item array.
+  if (!Array.isArray(params.unwindPath)) {
+    params.unwindPath = [params.unwindPath];
+  }
 }
 
 /**
@@ -194,8 +202,7 @@ function replaceQuotationMarks(stringifiedElement, quotes) {
  * @returns {String} csv string
  */
 function createColumnContent(params, str) {
-  var dataRows = createDataRows(params);
-  dataRows.forEach(function (dataElement) {
+  createDataRows(params.data, params.unwindPath).forEach(function (dataElement) {
     //if null do nothing, if empty object without includeEmptyRows do nothing
     if (dataElement && (Object.getOwnPropertyNames(dataElement).length > 0 || params.includeEmptyRows)) {
       var line = '';
@@ -280,33 +287,57 @@ function createColumnContent(params, str) {
 }
 
 /**
- * Performs the unwind logic if necessary to convert single JSON document into multiple rows
- * @param params
+ * 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
  */
-function createDataRows(params) {
-  var dataRows = params.data;
-
-  if (params.unwindPath) {
-    dataRows = [];
-    params.data.forEach(function(dataEl) {
-      var unwindArray = lodashGet(dataEl, params.unwindPath);
-      var isArr = Array.isArray(unwindArray);
-
-      if (isArr && unwindArray.length) {
-        unwindArray.forEach(function(unwindEl) {
-          var dataCopy = lodashCloneDeep(dataEl);
-          lodashSet(dataCopy, params.unwindPath, unwindEl);
-          dataRows.push(dataCopy);
-        });
-      } else if (isArr && !unwindArray.length) {
-        var dataCopy = lodashCloneDeep(dataEl);
-        lodashSet(dataCopy, params.unwindPath, undefined);
-        dataRows.push(dataCopy);
-      } else {
-        dataRows.push(dataEl);
-      }
+function createDataRows(originalData, unwindPaths) {
+  var dataRows = [];
+  if (unwindPaths.length) {
+    originalData.forEach(function(dataElement) {
+      var dataRow = [dataElement];
+
+      unwindPaths.forEach(function(unwindPath) {
+        dataRow = unwindRows(dataRow, unwindPath);
+      });
+
+      Array.prototype.push.apply(dataRows, dataRow);
     });
+  } else {
+    dataRows = originalData;
   }
 
   return dataRows;
 }
+
+/**
+ * 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
+ */
+function unwindRows(inputRows, unwindPath) {
+  var outputRows = [];
+  inputRows.forEach(function(dataEl) {
+    var unwindArray = lodashGet(dataEl, unwindPath);
+    var isArr = Array.isArray(unwindArray);
+
+    if (isArr && unwindArray.length) {
+      unwindArray.forEach(function(unwindEl) {
+        var dataCopy = lodashCloneDeep(dataEl);
+        lodashSet(dataCopy, unwindPath, unwindEl);
+        outputRows.push(dataCopy);
+      });
+    } else if (isArr && !unwindArray.length) {
+      var dataCopy = lodashCloneDeep(dataEl);
+      lodashSet(dataCopy, unwindPath, undefined);
+      outputRows.push(dataCopy);
+    } else {
+      outputRows.push(dataEl);
+    }
+  });
+  return outputRows;
+}

package.json

@@ -39,11 +39,11 @@
     "commander": "^2.8.1",
     "debug": "^2.2.0",
     "flat": "^2.0.0",
-    "lodash.flatten": "^4.2.0",
-    "lodash.get": "^4.3.0",
+    "lodash.flatten": "^4.4.0",
+    "lodash.get": "^4.4.0",
     "lodash.set": "^4.3.0",
-    "lodash.uniq": "^4.3.0",
-    "lodash.clonedeep": "^4.3.0",
+    "lodash.uniq": "^4.5.0",
+    "lodash.clonedeep": "^4.5.0",
     "path-is-absolute": "^1.0.0"
   },
   "devDependencies": {

test/fixtures/csv/unwind2.csv

@@ -0,0 +1,7 @@
+"carModel","price","items.name","items.color","items.items.position","items.items.color"
+"BMW",15000,"airbag","white",,
+"BMW",15000,"dashboard","black",,
+"Porsche",30000,"airbag",,"left","white"
+"Porsche",30000,"airbag",,"right","gray"
+"Porsche",30000,"dashboard",,"left","gray"
+"Porsche",30000,"dashboard",,"right","black"

test/fixtures/json/unwind2.json

@@ -0,0 +1,44 @@
+[
+    {
+        "carModel": "BMW",
+        "price": 15000,
+        "items": [
+            {
+                "name": "airbag",
+                "color": "white"
+            }, {
+                "name": "dashboard",
+                "color": "black"
+            }
+        ]
+    }, {
+        "carModel": "Porsche",
+        "price": 30000,
+        "items": [
+            {
+                "name": "airbag",
+                "items": [
+                    {
+                        "position": "left",
+                        "color": "white"
+                    }, {
+                        "position": "right",
+                        "color": "gray"
+                    }
+                ]
+            },
+            {
+                "name": "dashboard",
+                "items": [
+                    {
+                        "position": "left",
+                        "color": "gray"
+                    }, {
+                        "position": "right",
+                        "color": "black"
+                    }
+                ]
+            }
+        ]
+    }
+]

test/helpers/load-fixtures.js

@@ -28,7 +28,8 @@ var fixtures = [
   'emptyRow',
   'emptyRowNotIncluded',
   'emptyRowDefaultValues',
-  'unwind'
+  'unwind',
+  'unwind2'
 ];
 
 /*eslint-disable no-console*/

test/index.js

@@ -14,6 +14,7 @@ var jsonTrailingBackslash = require('./fixtures/json/trailingBackslash');
 var jsonOverriddenDefaultValue = require('./fixtures/json/overridenDefaultValue');
 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 csvFixtures = {};
 
@@ -409,7 +410,8 @@ async.parallel(loadFixtures(csvFixtures), function (err) {
 
   test('should escape " when preceeded by \\', function (t){
     json2csv({
-      data: [{field: '\\"'}]
+      data: [{field: '\\"'}],
+      newLine: '\n'
     }, function (error, csv){
       t.error(error);
       t.equal(csv, '"field"\n"\\""');
@@ -618,6 +620,19 @@ async.parallel(loadFixtures(csvFixtures), function (err) {
     })
   });
 
+
+  test('should unwind twice an array into multiple rows', function(t) {
+    json2csv({
+      data: jsonUnwind2,
+      fields: ['carModel', 'price', 'items.name', 'items.color', 'items.items.position', 'items.items.color'],
+      unwindPath: ['items', 'items.items']
+    }, function(error, csv) {
+      t.error(error);
+      t.equal(csv, csvFixtures.unwind2);
+      t.end()
+    })
+  });
+
   test('should not preserve new lines in values by default', function(t) {
     json2csv({
       data: jsonNewLine,