feat: add bracketedArray option

README.md

@@ -90,6 +90,9 @@ The `options` object may contain the following:
   to be used with: when `platform` is `win32`, line terminations are
   CR+LF, for other platforms line termination is LF.  By default the
   current platform name is used.
+* `bracketedArrays` Boolean to specify whether array values are appended
+  with `[]`.  By default this is true but there are some ini parsers
+  that instead treat duplicate names as arrays.
 
 For backwards compatibility reasons, if a `string` options is passed
 in, then it is assumed to be the `section` value.

lib/ini.js

@@ -8,18 +8,20 @@ const encode = (obj, opt = {}) => {
   opt.newline = opt.newline === true
   /* istanbul ignore next */
   opt.platform = opt.platform || process?.platform
+  opt.bracketedArray = opt.bracketedArray !== false
 
   /* istanbul ignore next */
   const eol = opt.platform === 'win32' ? '\r\n' : '\n'
   const separator = opt.whitespace ? ' = ' : '='
   const children = []
   let out = ''
+  const arraySuffix = opt.bracketedArray ? '[]' : ''
 
   for (const k of Object.keys(obj)) {
     const val = obj[k]
     if (val && Array.isArray(val)) {
       for (const item of val) {
-        out += safe(k + '[]') + separator + safe(item) + eol
+        out += safe(`${k}${arraySuffix}`) + separator + safe(item) + eol
       }
     } else if (val && typeof val === 'object') {
       children.push(k)
@@ -75,13 +77,15 @@ function splitSections (str, separator) {
   return sections
 }
 
-const decode = str => {
+const decode = (str, opt = {}) => {
+  opt.bracketedArray = opt.bracketedArray !== false
   const out = Object.create(null)
   let p = out
   let section = null
   //          section          |key      = value
   const re = /^\[([^\]]*)\]\s*$|^([^=]+)(=(.*))?$/i
   const lines = str.split(/[\r\n]+/g)
+  const duplicates = {}
 
   for (const line of lines) {
     if (!line || line.match(/^\s*[;#]/) || line.match(/^\s*$/)) {
@@ -103,7 +107,13 @@ const decode = str => {
       continue
     }
     const keyRaw = unsafe(match[2])
-    const isArray = keyRaw.length > 2 && keyRaw.slice(-2) === '[]'
+    let isArray
+    if (opt.bracketedArray) {
+      isArray = keyRaw.length > 2 && keyRaw.slice(-2) === '[]'
+    } else {
+      duplicates[keyRaw] = (duplicates?.[keyRaw] || 0) + 1
+      isArray = duplicates[keyRaw] > 1
+    }
     const key = isArray ? keyRaw.slice(0, -2) : keyRaw
     if (key === '__proto__') {
       continue

tap-snapshots/test/duplicate-properties.js.test.cjs

@@ -0,0 +1,57 @@
+/* IMPORTANT
+ * This snapshot file is auto-generated, but designed for humans.
+ * It should be checked into source control and tracked carefully.
+ * Re-generate by setting TAP_SNAPSHOT=1 and running tests.
+ * Make sure to inspect the output below.  Do not ignore changes!
+ */
+'use strict'
+exports[`test/duplicate-properties.js TAP decode duplicate properties with bracketedArray=false > must match snapshot 1`] = `
+Null Object {
+  "ar": Array [
+    "three",
+  ],
+  "ar[]": "one",
+  "b": Array [
+    "2",
+    "3",
+    "3",
+  ],
+  "brr": "1",
+  "str": "3",
+  "zr": "123",
+  "zr[]": "deedee",
+}
+`
+
+exports[`test/duplicate-properties.js TAP decode with duplicate properties > must match snapshot 1`] = `
+Null Object {
+  "ar": Array [
+    "one",
+    "three",
+  ],
+  "brr": "3",
+  "str": "3",
+  "zr": Array [
+    "deedee",
+    "123",
+  ],
+}
+`
+
+exports[`test/duplicate-properties.js TAP encode duplicate properties with bracketedArray=false > must match snapshot 1`] = `
+ar=1
+ar=2
+ar=3
+br=1
+br=2
+
+`
+
+exports[`test/duplicate-properties.js TAP encode with duplicate properties > must match snapshot 1`] = `
+ar[]=1
+ar[]=2
+ar[]=3
+br[]=1
+br[]=2
+
+`

test/duplicate-properties.js

@@ -0,0 +1,38 @@
+const i = require('../')
+const tap = require('tap')
+const test = tap.test
+const fs = require('fs')
+const path = require('path')
+
+const fixture = path.resolve(__dirname, './fixtures/duplicate.ini')
+const data = fs.readFileSync(fixture, 'utf8')
+
+test('decode with duplicate properties', function (t) {
+  const d = i.decode(data)
+  t.matchSnapshot(d)
+  t.end()
+})
+
+test('encode with duplicate properties', function (t) {
+  const e = i.encode({
+    ar: ['1', '2', '3'],
+    br: ['1', '2'],
+  })
+  t.matchSnapshot(e)
+  t.end()
+})
+
+test('decode duplicate properties with bracketedArray=false', function (t) {
+  const d = i.decode(data, { bracketedArray: false })
+  t.matchSnapshot(d)
+  t.end()
+})
+
+test('encode duplicate properties with bracketedArray=false', function (t) {
+  const e = i.encode({
+    ar: ['1', '2', '3'],
+    br: ['1', '2'],
+  }, { bracketedArray: false })
+  t.matchSnapshot(e)
+  t.end()
+})

test/fixtures/duplicate.ini

@@ -0,0 +1,9 @@
+zr[] = deedee
+zr=123
+ar[] = one
+ar[] = three
+str = 3
+brr = 1
+brr = 2
+brr = 3
+brr = 3