Add new option foldChars (#14)

README.md

@@ -46,7 +46,8 @@ const defaultOptions = {
   latin1: true,         // default encoding for .properties files
   lineWidth: 80,        // use null to disable
   newline: '\n',        // Windows uses \r\n
-  pathSep: '.'          // if non-default, use the same in parse()
+  pathSep: '.',         // if non-default, use the same in parse()
+  foldChars: '\f\t .'   // preferred characters for line folding
 }
 ```
 

lib/index.d.ts

@@ -78,6 +78,7 @@ interface StringifyOptions {
   lineWidth?: 80 | number,        // use null to disable
   newline?: '\n' | string,        // Windows uses \r\n
   pathSep?: '.' | string          // if non-default, use the same in parse()
+  foldChars?: '\f\t .' | string
 }
 
 /**

lib/stringify.js

@@ -19,7 +19,7 @@ const escapeValue = value => escape(value).replace(/^ /, '\\ ')
 const prefixComment = (str, prefix) =>
   str.replace(/^\s*([#!][ \t\f]*)?/g, prefix)
 
-function fold({ indent, latin1, lineWidth, newline }, key, value) {
+function fold({ indent, latin1, lineWidth, newline, foldChars }, key, value) {
   const printKey = escapeNonPrintable(key, latin1)
   const printValue = escapeNonPrintable(value, latin1)
   let line = printKey + printValue
@@ -52,18 +52,20 @@ function fold({ indent, latin1, lineWidth, newline }, key, value) {
               end = i + 1
               break
             case ' ':
+            case '=':
+            case ':':
+              if (foldChars.includes(line[i])) split = i + 1
+              break
             case 'f':
+              if (foldChars.includes('\f')) split = i + 1
+              break
             case 't':
-              split = i + 1
+              if (foldChars.includes('\t')) split = i + 1
               break
           }
           break
-        case '\f':
-        case '\t':
-        case ' ':
-        case '.':
-          split = i + 1
-          break
+        default:
+          if (foldChars.includes(ch)) split = i + 1
       }
     }
     if (end) {
@@ -114,13 +116,26 @@ function stringify(
     latin1 = true,
     lineWidth = 80,
     newline = '\n',
-    pathSep = '.'
+    pathSep = '.',
+    foldChars = '\f\t .'
   } = {}
 ) {
   if (!input) return ''
   if (!Array.isArray(input)) input = toLines(input, pathSep, defaultKey)
-  const lineOpt = { indent, latin1, lineWidth, newline: '\\' + newline }
-  const commentOpt = { indent: commentPrefix, latin1, lineWidth, newline }
+  const lineOpt = {
+    indent,
+    latin1,
+    lineWidth,
+    newline: '\\' + newline,
+    foldChars
+  }
+  const commentOpt = {
+    indent: commentPrefix,
+    latin1,
+    lineWidth,
+    newline,
+    foldChars
+  }
   return input
     .map(line => {
       switch (true) {

tests/folding.tests.js

@@ -0,0 +1,136 @@
+const { stringify } = require('../lib/index')
+
+describe('Folding', () => {
+  test('long value starts on new line', () => {
+    const lines = [
+      ['k0', '0 val0'],
+      ['k1', '1 value1'],
+      ['key', 'v0'],
+      ['key1', 'value1'],
+      ['key2', 'value2 continues']
+    ]
+    expect(stringify(lines, { indent: '  ', lineWidth: 8 })).toBe(
+      `\
+k0 = \\
+  0 val0
+k1 = \\
+  1 \\
+  value1
+key = v0
+key1 = \\
+  value1
+key2 = \\
+  value2\\
+  \\ \\
+  contin\\
+  ues`
+    )
+  })
+
+  test('values after long keys do not start on new line', () => {
+    const lines = [
+      ['longish key', 'v0'],
+      ['longkeyxx', '42'],
+      ['somelongkey', 'withlongvalue']
+    ]
+    expect(stringify(lines, { indent: '  ', lineWidth: 8 })).toBe(
+      `\
+longish\\ \\
+  key = \\
+  v0
+longkeyx\\
+  x = 42
+somelong\\
+  key = \\
+  withlo\\
+  ngvalu\\
+  e`
+    )
+  })
+
+  describe('foldChars', () => {
+    const lines = [
+      ['key0', '12 345678'],
+      ['key1', '12.345678'],
+      ['key2', '12\t345678'],
+      ['key3', '12\f345678'],
+      ['key4', ' 12 345678'],
+      ['key5', '12,345678']
+    ]
+    test('default', () => {
+      expect(stringify(lines, { indent: '  ', lineWidth: 8 })).toBe(
+        `\
+key0 = \\
+  12 \\
+  345678
+key1 = \\
+  12.\\
+  345678
+key2 = \\
+  12\\t\\
+  345678
+key3 = \\
+  12\\f\\
+  345678
+key4 = \\
+  \\ 12 \\
+  345678
+key5 = \\
+  12,345\\
+  678`
+      )
+    })
+
+    test('empty', () => {
+      expect(
+        stringify(lines, { indent: '  ', lineWidth: 8, foldChars: '' })
+      ).toBe(
+        `\
+key0 = \\
+  12 345\\
+  678
+key1 = \\
+  12.345\\
+  678
+key2 = \\
+  12\\t34\\
+  5678
+key3 = \\
+  12\\f34\\
+  5678
+key4 = \\
+  \\ 12 3\\
+  45678
+key5 = \\
+  12,345\\
+  678`
+      )
+    })
+
+    test('custom', () => {
+      expect(
+        stringify(lines, { indent: '  ', lineWidth: 8, foldChars: ',' })
+      ).toBe(
+        `\
+key0 = \\
+  12 345\\
+  678
+key1 = \\
+  12.345\\
+  678
+key2 = \\
+  12\\t34\\
+  5678
+key3 = \\
+  12\\f34\\
+  5678
+key4 = \\
+  \\ 12 3\\
+  45678
+key5 = \\
+  12,\\
+  345678`
+      )
+    })
+  })
+})