Serializing const type with ' character (#658)

* Fixed case when serializing const type with value that contains ' character

* Extracted single quote as regex and used replace instead of replaceAll

Author: seidelmartin

index.js

@@ -12,6 +12,8 @@ const Serializer = require('./lib/serializer')
 const Validator = require('./lib/validator')
 const Location = require('./lib/location')
 
+const SINGLE_TICK = /'/g
+
 let largeArraySize = 2e4
 let largeArrayMechanism = 'default'
 
@@ -834,7 +836,7 @@ function buildConstSerializer (location, input) {
     `
   }
 
-  code += `json += '${JSON.stringify(schema.const)}'`
+  code += `json += '${JSON.stringify(schema.const).replace(SINGLE_TICK, "\\'")}'`
 
   if (hasNullType) {
     code += `

test/const.test.js

@@ -82,6 +82,26 @@ test('schema with const string and no input', (t) => {
   t.ok(validate(JSON.parse(output)), 'valid schema')
 })
 
+test('schema with const string that contains \'', (t) => {
+  t.plan(2)
+
+  const schema = {
+    type: 'object',
+    properties: {
+      foo: { const: "'bar'" }
+    }
+  }
+
+  const validate = validator(schema)
+  const stringify = build(schema)
+  const output = stringify({
+    foo: "'bar'"
+  })
+
+  t.equal(output, '{"foo":"\'bar\'"}')
+  t.ok(validate(JSON.parse(output)), 'valid schema')
+})
+
 test('schema with const number', (t) => {
   t.plan(2)