add support for date-time formats (#195)

Author: ilaif

README.md

@@ -2,7 +2,7 @@
 
 [![js-standard-style](https://img.shields.io/badge/code%20style-standard-brightgreen.svg?style=flat)](http://standardjs.com/)
 ![Ci Workflow](https://github.com/fastify/fast-json-stringify/workflows/CI%20workflow/badge.svg)
-[![NPM downloads](https://img.shields.io/npm/dm/fast-json-stringify.svg?style=flat)](https://www.npmjs.com/package/fast-json-stringify) 
+[![NPM downloads](https://img.shields.io/npm/dm/fast-json-stringify.svg?style=flat)](https://www.npmjs.com/package/fast-json-stringify)
 
 
 __fast-json-stringify__ is significantly faster than `JSON.stringify()` for small payloads. Its performance advantage shrinks as your payload grows. It pairs well with [__flatstr__](https://www.npmjs.com/package/flatstr), which triggers a V8 optimization that improves performance when eventually converting the string to a `Buffer`.
@@ -105,11 +105,34 @@ And nested ones, too.
 <a name="specific"></a>
 #### Specific use cases
 
-| Instance   | Serialized as                |
-| -----------|------------------------------|
-| `Date`     | `string` via `toISOString()` |
-| `RegExp`   | `string`                     |
-| `BigInt`   | `integer` via `toString`     |
+| Instance | Serialized as                |
+| -------- | ---------------------------- |
+| `Date`   | `string` via `toISOString()` |
+| `RegExp` | `string`                     |
+| `BigInt` | `integer` via `toString`     |
+
+[JSON Schema built-in formats](https://json-schema.org/understanding-json-schema/reference/string.html#built-in-formats) for dates are supported and will be serialized as:
+
+| Format      | Serialized format example  |
+| ----------- | -------------------------- |
+| `date-time` | `2020-04-03T09:11:08.615Z` |
+| `date`      | `2020-04-03`               |
+| `time`      | `09:11:08`                 |
+
+Example with a MomentJS object:
+
+```javascript
+const moment = require('moment')
+
+const stringify = fastJson({
+  title: 'Example Schema with string date-time field',
+  type: 'string',
+  format: 'date-time'
+}
+
+console.log(stringify(moment())) // '"YYYY-MM-DDTHH:mm:ss.sssZ"'
+```
+
 
 <a name="required"></a>
 #### Required
@@ -444,7 +467,7 @@ const stringify = fastJson(schema, { schema: externalSchema })
 
 <a name="long"></a>
 #### Long integers
-By default the library will handle automatically [BigInt](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt) from Node.js v10.3 and above.  
+By default the library will handle automatically [BigInt](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt) from Node.js v10.3 and above.
 If you can't use BigInts in your environment, long integers (64-bit) are also supported using the [long](https://github.com/dcodeIO/long.js) module.
 Example:
 ```javascript

example.js

@@ -1,5 +1,6 @@
 'use strict'
 
+const moment = require('moment')
 const fastJson = require('.')
 const stringify = fastJson({
   title: 'Example Schema',
@@ -18,6 +19,10 @@ const stringify = fastJson({
     now: {
       type: 'string'
     },
+    birthdate: {
+      type: ['string'],
+      format: 'date-time'
+    },
     reg: {
       type: 'string'
     },
@@ -48,6 +53,10 @@ const stringify = fastJson({
     },
     test: {
       type: 'number'
+    },
+    date: {
+      type: 'string',
+      format: 'date-time'
     }
   },
   additionalProperties: {
@@ -60,10 +69,12 @@ console.log(stringify({
   lastName: 'Collina',
   age: 32,
   now: new Date(),
+  birthdate: moment(),
   reg: /"([^"]|\\")*"/,
   foo: 'hello',
   numfoo: 42,
   test: 42,
+  date: moment(),
   strtest: '23',
   arr: [{ str: 'stark' }, { str: 'lannister' }],
   obj: { bool: true },

index.js

@@ -4,6 +4,7 @@
 
 var Ajv = require('ajv')
 var merge = require('deepmerge')
+
 var util = require('util')
 var validate = require('./schema-validator')
 var stringSimilarity = null
@@ -52,9 +53,13 @@ function build (schema, options) {
   `
 
   code += `
+    ${$pad2Zeros.toString()}
     ${$asString.toString()}
     ${$asStringNullable.toString()}
     ${$asStringSmall.toString()}
+    ${$asDatetime.toString()}
+    ${$asDate.toString()}
+    ${$asTime.toString()}
     ${$asNumber.toString()}
     ${$asNumberNullable.toString()}
     ${$asIntegerNullable.toString()}
@@ -94,7 +99,7 @@ function build (schema, options) {
       code = buildObject(schema, code, main, options.schema, fullSchema)
       break
     case 'string':
-      main = schema.nullable ? $asStringNullable.name : $asString.name
+      main = schema.nullable ? $asStringNullable.name : getStringSerializer(schema.format)
       break
     case 'integer':
       main = schema.nullable ? $asIntegerNullable.name : $asInteger.name
@@ -209,6 +214,21 @@ function hasIf (schema) {
   return /"if":{/.test(str) && /"then":{/.test(str)
 }
 
+const stringSerializerMap = {
+  'date-time': '$asDatetime',
+  date: '$asDate',
+  time: '$asTime'
+}
+
+function getStringSerializer (format) {
+  return stringSerializerMap[format] || '$asString'
+}
+
+function $pad2Zeros (num) {
+  var s = '00' + num
+  return s[s.length - 2] + s[s.length - 1]
+}
+
 function $asNull () {
   return 'null'
 }
@@ -248,6 +268,42 @@ function $asBooleanNullable (bool) {
   return bool === null ? null : $asBoolean(bool)
 }
 
+function $asDatetime (date) {
+  if (date instanceof Date) {
+    return '"' + date.toISOString() + '"'
+  } else if (typeof date.toISOString === 'function') {
+    return '"' + date.toISOString() + '"'
+  } else {
+    return $asString(date)
+  }
+}
+
+function $asDate (date) {
+  if (date instanceof Date) {
+    var year = new Intl.DateTimeFormat('en', { year: 'numeric' }).format(date)
+    var month = new Intl.DateTimeFormat('en', { month: '2-digit' }).format(date)
+    var day = new Intl.DateTimeFormat('en', { day: '2-digit' }).format(date)
+    return '"' + year + '-' + month + '-' + day + '"'
+  } else if (typeof date.format === 'function') {
+    return '"' + date.format('YYYY-MM-DD') + '"'
+  } else {
+    return $asString(date)
+  }
+}
+
+function $asTime (date) {
+  if (date instanceof Date) {
+    var hour = new Intl.DateTimeFormat('en', { hour: 'numeric', hour12: false }).format(date)
+    var minute = new Intl.DateTimeFormat('en', { minute: 'numeric' }).format(date)
+    var second = new Intl.DateTimeFormat('en', { second: 'numeric' }).format(date)
+    return '"' + $pad2Zeros(hour) + ':' + $pad2Zeros(minute) + ':' + $pad2Zeros(second) + '"'
+  } else if (typeof date.format === 'function') {
+    return '"' + date.format('HH:mm:ss') + '"'
+  } else {
+    return $asString(date)
+  }
+}
+
 function $asString (str) {
   if (str instanceof Date) {
     return '"' + str.toISOString() + '"'
@@ -317,6 +373,8 @@ function addPatternProperties (schema, externalSchema, fullSchema) {
       pp[regex] = refFinder(pp[regex].$ref, fullSchema, externalSchema)
     }
     var type = pp[regex].type
+    var format = pp[regex].format
+    var stringSerializer = getStringSerializer(format)
     code += `
         if (/${regex.replace(/\\*\//g, '\\/')}/.test(keys[i])) {
     `
@@ -340,7 +398,7 @@ function addPatternProperties (schema, externalSchema, fullSchema) {
     } else if (type === 'string') {
       code += `
           ${addComma}
-          json += $asString(keys[i]) + ':' + $asString(obj[keys[i]])
+          json += $asString(keys[i]) + ':' + ${stringSerializer}(obj[keys[i]])
       `
     } else if (type === 'integer') {
       code += `
@@ -394,6 +452,8 @@ function additionalProperty (schema, externalSchema, fullSchema) {
   }
 
   var type = ap.type
+  var format = ap.format
+  var stringSerializer = getStringSerializer(format)
   if (type === 'object') {
     code += buildObject(ap, '', 'buildObjectAP', externalSchema)
     code += `
@@ -414,7 +474,7 @@ function additionalProperty (schema, externalSchema, fullSchema) {
   } else if (type === 'string') {
     code += `
         ${addComma}
-        json += $asString(keys[i]) + ':' + $asString(obj[keys[i]])
+        json += $asString(keys[i]) + ':' + ${stringSerializer}(obj[keys[i]])
     `
   } else if (type === 'integer') {
     code += `
@@ -941,7 +1001,8 @@ function nested (laterCode, name, key, schema, externalSchema, fullSchema, subKe
       `
       break
     case 'string':
-      code += nullable ? `json += obj${accessor} === null ? null : $asString(obj${accessor})` : `json += $asString(obj${accessor})`
+      var stringSerializer = getStringSerializer(schema.format)
+      code += nullable ? `json += obj${accessor} === null ? null : ${stringSerializer}(obj${accessor})` : `json += ${stringSerializer}(obj${accessor})`
       break
     case 'integer':
       code += nullable ? `json += obj${accessor} === null ? null : $asInteger(obj${accessor})` : `json += $asInteger(obj${accessor})`
@@ -1010,7 +1071,7 @@ function nested (laterCode, name, key, schema, externalSchema, fullSchema, subKe
           var nestedResult = nested(laterCode, name, key, tempSchema, externalSchema, fullSchema, subKey)
           if (type === 'string') {
             code += `
-              ${index === 0 ? 'if' : 'else if'}(typeof obj${accessor} === "${type}" || obj${accessor} instanceof Date || obj${accessor} instanceof RegExp)
+              ${index === 0 ? 'if' : 'else if'}(typeof obj${accessor} === "${type}" || obj${accessor} instanceof Date || typeof obj${accessor}.toISOString === "function" || obj${accessor} instanceof RegExp)
                 ${nestedResult.code}
             `
           } else if (type === 'null') {

package.json

@@ -35,6 +35,7 @@
     "is-my-json-valid": "^2.20.0",
     "json-strify": "^0.1.7",
     "long": "^4.0.0",
+    "moment": "^2.24.0",
     "pre-commit": "^1.2.2",
     "proxyquire": "^2.1.3",
     "semver": "^7.1.0",

test/array.test.js

@@ -1,5 +1,6 @@
 'use strict'
 
+const moment = require('moment')
 const test = require('tap').test
 const validator = require('is-my-json-valid')
 const build = require('..')
@@ -164,3 +165,28 @@ test('invalid items throw', (t) => {
   const stringify = build(schema)
   t.throws(() => stringify({ args: ['invalid'] }))
 })
+
+test('moment array', (t) => {
+  t.plan(1)
+  const schema = {
+    type: 'object',
+    properties: {
+      times: {
+        type: 'array',
+        items: {
+          type: 'string',
+          format: 'date-time'
+        }
+      }
+    }
+  }
+  const stringify = build(schema)
+  try {
+    const value = stringify({
+      times: [moment('2018-04-21T07:52:31.017Z')]
+    })
+    t.is(value, '{"times":["2018-04-21T07:52:31.017Z"]}')
+  } catch (e) {
+    t.fail(e)
+  }
+})