Handle line breaks and carriage returns correctly

src/utils/parseFormData.test.ts

@@ -25,6 +25,18 @@ test('should normalize one pair', (t) => {
   t.deepEqual(ret, expected)
 })
 
+test('should normalize line break', (t) => {
+  const data = 'value=1&text=Several+words%0D%0Ahere%0D%0Aand+here'
+  const expected = {
+    value: 1,
+    text: 'Several words\nhere\nand here',
+  }
+
+  const ret = parseFormData(data)
+
+  t.deepEqual(ret, expected)
+})
+
 test('should normalize keys with bracket postfix into array', (t) => {
   const data = 'value=1&lines[]=Several+words&lines[]=on+several&lines[]=lines'
   const expected = {

src/utils/parseFormData.ts

@@ -6,9 +6,11 @@ const parseObject = (value: string) => {
   }
 }
 
+const fixLineBreak = (value: string) => value.replace(/%0D%0A/g, '%0A')
+
 const parseValue = (value?: string) =>
   typeof value === 'string'
-    ? parseObject(decodeURIComponent(value).replace(/\+/g, ' '))
+    ? parseObject(decodeURIComponent(fixLineBreak(value)).replace(/\+/g, ' '))
     : undefined
 
 function reducePair(

src/utils/stringifyFormData.test.ts

@@ -29,6 +29,30 @@ test('should serialize uri', (t) => {
   t.is(ret, expected)
 })
 
+test('should serialize line break', (t) => {
+  const data = {
+    value: 1,
+    text: 'Several words\nhere\nand here',
+  }
+  const expected = 'value=1&text=Several+words%0D%0Ahere%0D%0Aand+here'
+
+  const ret = stringifyFormData(data)
+
+  t.is(ret, expected)
+})
+
+test('should serialize carriage return and line break', (t) => {
+  const data = {
+    value: 1,
+    text: 'Several words\r\nhere\r\nand here',
+  }
+  const expected = 'value=1&text=Several+words%0D%0Ahere%0D%0Aand+here'
+
+  const ret = stringifyFormData(data)
+
+  t.is(ret, expected)
+})
+
 test('should serialize array to several keys with bracket postfix', (t) => {
   const data = {
     value: 1,

src/utils/stringifyFormData.ts

@@ -7,8 +7,11 @@ const formatObject = (value: unknown) =>
       ? value.toISOString()
       : String(value)
 
+const fixLineBreak = (value: unknown) =>
+  typeof value === 'string' ? value.replace(/(^|[^\r])\n/g, '$1\r\n') : value
+
 const formatValue = (value: unknown) =>
-  encodeURIComponent(formatObject(value)).replace(/%20/g, '+')
+  encodeURIComponent(formatObject(fixLineBreak(value))).replace(/%20/g, '+')
 
 function mapEntry([key, value]: [string, unknown]) {
   if (Array.isArray(value)) {