fix: lost headers after broken lines (#151)

* fix: strict false - broken header keys

* fix: do not replace global headers

* fix: if header exists object properties are set

* fix: move added properties to end

* fix: add missing informations

README.md

@@ -251,9 +251,13 @@ Maximum number of bytes per row. An error is thrown if a line exeeds this value.
 #### strict
 
 Type: `Boolean`<br>
+Default: `false`
 
 If `true`, instructs the parser that the number of columns in each row must match
-the number of `headers` specified.
+the number of `headers` specified or throws an exception.
+if `false`: the headers are mapped to the column index
+   less columns: any missing column in the middle will result in a wrong property mapping!
+   more columns: the aditional columns will create a "_"+index properties - eg. "_10":"value"
 
 ## Events
 

index.js

@@ -176,14 +176,15 @@ class CsvParser extends Transform {
   }
 
   writeRow (cells) {
-    if (this.headers === false || cells.length > this.headers.length) {
-      this.headers = cells.map((value, index) => index)
-    }
+    const headers = (this.headers === false) ? cells.map((value, index) => index) : this.headers
 
     const row = cells.reduce((o, cell, index) => {
-      const header = this.headers[index]
-      if (header !== null) {
+      const header = headers[index]
+      if (header === null) return o // skip columns
+      if (header !== undefined) {
         o[header] = cell
+      } else {
+        o[`_${index}`] = cell
       }
       return o
     }, {})

test/fixtures/strict-false-less-columns.csv

@@ -0,0 +1,4 @@
+a,b,c
+1,2,3
+4,5
+6,7,8

test/fixtures/strict-false-more-columns.csv

@@ -0,0 +1,4 @@
+a,b,c
+1,2,3
+4,5,6,7
+8,9,10

test/snapshots/strictNo.test.js.md

@@ -0,0 +1,57 @@
+# Snapshot report for `test/strictNo.test.js`
+
+The actual snapshot is saved in `strictNo.test.js.snap`.
+
+Generated by [AVA](https://ava.li).
+
+## strict: false - less columns
+
+> first row
+
+    {
+      a: '1',
+      b: '2',
+      c: '3',
+    }
+
+> broken row
+
+    {
+      a: '4',
+      b: '5',
+    }
+
+> last row
+
+    {
+      a: '6',
+      b: '7',
+      c: '8',
+    }
+
+## strict: false - more columns
+
+> first row
+
+    {
+      a: '1',
+      b: '2',
+      c: '3',
+    }
+
+> broken row
+
+    {
+      _3: '7',
+      a: '4',
+      b: '5',
+      c: '6',
+    }
+
+> last row
+
+    {
+      a: '8',
+      b: '9',
+      c: '10',
+    }

test/strictNo.test.js

@@ -0,0 +1,41 @@
+const test = require('ava')
+
+const { collect } = require('./helpers/helper')
+
+test.cb('strict: false - more columns', (t) => {
+  const verify = (err, lines) => {
+    const headersFirstLine = Object.keys(lines[0])
+    const headersBrokenLine = Object.keys(lines[1])
+    const headersLastLine = Object.keys(lines[2])
+    t.false(err, 'no err')
+    t.deepEqual(headersFirstLine, headersLastLine)
+    t.deepEqual(headersBrokenLine, ['a', 'b', 'c', '_3'])
+    t.snapshot(lines[0], 'first row')
+    t.snapshot(lines[1], 'broken row')
+    t.snapshot(lines[2], 'last row')
+    t.is(lines.length, 3, '3 rows')
+    t.is(headersBrokenLine.length, 4, '4 columns')
+    t.end()
+  }
+
+  collect('strict-false-more-columns', { strict: false }, verify)
+})
+
+test.cb('strict: false - less columns', (t) => {
+  const verify = (err, lines) => {
+    const headersFirstLine = Object.keys(lines[0])
+    const headersBrokenLine = Object.keys(lines[1])
+    const headersLastLine = Object.keys(lines[2])
+    t.false(err, 'no err')
+    t.deepEqual(headersFirstLine, headersLastLine)
+    t.deepEqual(headersBrokenLine, ['a', 'b'])
+    t.snapshot(lines[0], 'first row')
+    t.snapshot(lines[1], 'broken row')
+    t.snapshot(lines[2], 'last row')
+    t.is(lines.length, 3, '3 rows')
+    t.is(headersBrokenLine.length, 2, '2 columns')
+    t.end()
+  }
+
+  collect('strict-false-less-columns', { strict: false }, verify)
+})