@omkartech/generate-schema
v1.2.0
Published
Generates a JSON schema from a given JSON file/JSON data
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@omkartech/generate-schema
Generate JSON Schema from JSON data with added date, UUID, enum, and length detection
This package extends generate-schema to detect ISO dates, datetimes, enums, minLength, maxLength and UUIDs from the JSON and add appropriate format and size limits.
Installation
npm install --save @omkartech/generate-schemaUsage
const generateSchema = require('@omkartech/generate-schema')Example
Generate JSON Schema with UUID and format detection (date, date-time)
const customers = [{
Id: '8198f931-f31d-4051-8964-5efe1d804a19',
FirstName: 'Om',
LastName: 'Tech',
Gender: 'Male',
BirthDate: '2001-01-03',
DateUpdated: '2019-01-17T22:23:21+00:00'
},
{
Id: 'abaa80cc-e0eb-4a33-8292-ec937ffe773b',
FirstName: 'Gabe',
LastName: 'Smith',
Gender: 'Female',
BirthDate: '1976-11-25',
DateUpdated: '2017-01-16T22:23:24+00:00'
}]
const schema = generateSchema.json('Customer', customers)Outputs
{
"$schema": "http://json-schema.org/draft-04/schema#",
"title": "Customer Set",
"type": "array",
"items": {
"type": "object",
"properties": {
"Id": {
"type": "string",
"minLength": 36,
"maxLength": 36
},
"FirstName": {
"type": "string"
},
"LastName": {
"type": "string"
},
"Gender": {
"type": "string"
},
"BirthDate": {
"type": "string",
"format": "date"
},
"DateUpdated": {
"type": "string",
"format": "date-time"
}
},
"required": [
"Id",
"FirstName",
"LastName",
"BirthDate",
"DateUpdated"
],
"title": "Customer"
}
}Example
Generate JSON Schema with popular format deduction
const Customers = [
{
Id: "8198f931-f31d-4051-8964-5efe1d804a19",
FirstName: "Om",
Gender: "Male",
BirthDate: "2000-04-01",
DivisionCode: "PRP",
NumberAndString: "test",
Salary: 1023.456787,
DateUpdated: "2018-01-16T23:33:01+00:00"
},
{
Id: "f0da3cca-a6ef-434b-bd54-e707e3e54a03",
FirstName: "Nate",
Gender: "Male",
BirthDate: "1999-05-01",
DivisionCode: "SFW",
NumberAndString: "test",
Salary: -10023.5,
DateUpdated: "2018-01-16T23:33:01+00:00"
},
{
Id: "8198f931-f31d-4051-8964-5efe1d804a19",
FirstName: "Reka",
Gender: "Female",
BirthDate: "2002-04-01",
DivisionCode: "HDW",
NumberAndString: "one",
Salary: 10023.7,
DateUpdated: "2018-01-16T23:33:01+00:00"
},
{
Id: "e895aa94-8329-48a1-9f16-5e675f620eb7_INACTIVE",
FirstName: "Nelly",
Gender: "Female",
BirthDate: "March 10",
DivisionCode: "2018-01-16T23:33:44+00:00",
NumberAndString: 10,
Salary: 10023.4501,
DateUpdated: "2018-01-16T23:33:44+00:00"
}
];
const schema = generateSchema.json('Customer', Customers, {
pickPopularFormat: true
})Outputs
If you observe the data in "DivisionCode" key some are string and some are date-time, without the option pickPopularFormats the format would be date-time, with option turned on it picks the format as string because the format "string" appears more times then date-time and string can hold any types.
{
"$schema": "http://json-schema.org/draft-04/schema#",
"title": "Customer Set",
"type": "array",
"items": {
"type": "object",
"properties": {
"Id": {
"type": "string",
"minLength": 36,
"maxLength": 36,
"format": "uuid"
},
"FirstName": {
"type": "string",
"format": "string"
},
"Gender": {
"type": "string",
"format": "string"
},
"BirthDate": {
"type": "string",
"format": "date"
},
"DivisionCode": {
"type": "string",
"format": "string"
},
"NumberAndString": {
"type": [
"string",
"number"
],
"format": "string"
},
"Salary": {
"type": "number",
"format": "number"
},
"DateUpdated": {
"type": "string",
"format": "date-time"
}
},
"required": [
"Id",
"FirstName",
"Gender",
"BirthDate",
"DivisionCode",
"NumberAndString",
"Salary",
"DateUpdated"
],
"title": "Customer"
}
}Example
Generate JSON Schema with format counts (but not with popular format)
const Customers = [
{
Id: "8198f931-f31d-4051-8964-5efe1d804a19",
FirstName: "Gabe",
Gender: "Male",
BirthDate: "2000-04-01",
DivisionCode: "PRP",
NumberAndString: "test",
Salary: 10023.456787,
DateUpdated: "2018-01-16T23:33:01+00:00"
},
{
Id: "f0da3cca-a6ef-434b-bd54-e707e3e54a03",
FirstName: "Neil",
Gender: "Male",
BirthDate: "1999-05-01",
DivisionCode: "SFW",
NumberAndString: "test",
Salary: -10023.5,
DateUpdated: "2018-01-16T23:33:01+00:00"
},
{
Id: "8198f931-f31d-4051-8964-5efe1d804a19",
FirstName: "Enu",
Gender: "Female",
BirthDate: "2002-04-01",
DivisionCode: "HDW",
NumberAndString: "one",
Salary: 10023.7,
DateUpdated: "2018-01-16T23:33:01+00:00"
},
{
Id: "e895aa94-8329-48a1-9f16-5e675f620eb7_INACTIVE",
FirstName: "Candy",
Gender: "Female",
BirthDate: "March 10",
DivisionCode: "2018-01-16T23:33:44+00:00",
NumberAndString: 10,
Salary: 10023.4501,
DateUpdated: "2018-01-16T23:33:44+00:00"
}
];
const schema = generateSchema.json('Customer', Customers, {
addFormatCounts: true
})Outputs
If you observe the data in "DivisionCode" key some are string and some are date-time. If you set addFormatCounts it will add how many times a particular format appears. DivisionCode will have a new output
formats: {date-time:1, string:3} meaning string appears 3 times and date-time appears 1 time.
This can be used by caller to determine the format instead of using the given format or picking the popular format.
{
"$schema": "http://json-schema.org/draft-04/schema#",
"title": "Customer Set",
"type": "array",
"items": {
"type": "object",
"properties": {
"Id": {
"type": "string",
"minLength": 36,
"maxLength": 36,
"format": "string",
"formats": {
"uuid": 3,
"string": 1
}
},
"FirstName": {
"type": "string",
"format": "string",
"formats": {
"string": 4
}
},
"Gender": {
"type": "string",
"format": "string",
"formats": {
"string": 4
}
},
"BirthDate": {
"type": "string",
"format": "string",
"formats": {
"date": 3,
"string": 1
}
},
"DivisionCode": {
"type": "string",
"format": "date-time",
"formats": {
"string": 3,
"date-time": 1
}
},
"NumberAndString": {
"type": [
"string",
"number"
],
"format": "number",
"formats": {
"string": 3,
"number": 1
}
},
"Salary": {
"type": "number",
"format": "number",
"formats": {
"number": 4
}
},
"DateUpdated": {
"type": "string",
"format": "date-time",
"formats": {
"date-time": 4
}
}
},
"required": [
"Id",
"FirstName",
"Gender",
"BirthDate",
"DivisionCode",
"NumberAndString",
"Salary",
"DateUpdated"
],
"title": "Customer"
}
}Example
Generate JSON Schema with enums and lengths
const schema = generateSchema.json('Customer', Customers,{
generateEnums: true,
maxEnumValues: 2,
generateLengths: true
})Outputs (With enums and lengths)
{
"$schema": "http://json-schema.org/draft-04/schema#",
"title": "Customer Set",
"type": "array",
"items": {
"type": "object",
"properties": {
"Id": {
"type": "string",
"minLength": 36,
"maxLength": 36,
"enum": [
"8198f931-f31d-4051-8964-5efe1d804a19",
"abaa80cc-e0eb-4a33-8292-ec937ffe773b"
]
},
"FirstName": {
"type": "string",
"enum": [
"John",
"Cindy"
],
"minLength": 4,
"maxLength": 5
},
"LastName": {
"type": "string",
"enum": [
"Doe",
"Kline"
],
"minLength": 3,
"maxLength": 5
},
"Gender": {
"type": "string",
"enum": [
"Male",
"Female"
],
"minLength": 4,
"maxLength": 6
},
"BirthDate": {
"type": "string",
"format": "date",
"enum": [
"2000-04-01",
"1974-10-25"
],
"minLength": 10,
"maxLength": 10
},
"DateUpdated": {
"type": "string",
"format": "date-time",
"enum": [
"2018-01-16T23:33:01+00:00",
"2018-01-16T23:33:44+00:00"
],
"minLength": 25,
"maxLength": 25
}
},
"required": [
"Id",
"FirstName",
"LastName",
"Gender",
"BirthDate",
"DateUpdated"
],
"title": "Customer"
}
}
Methods
generateSchema.json(String title, Mixed object, [Object options])
Generates JSON Schema from an Object or Array
- title of JSON Schema
- object must be of type Object or Array
- options is optional
Options
generateEnumsflag is used to add enum list to schema for string types and defaults to falsemaxEnumValuesis used to limit the number of enum values detected and defaults to 20generateLengthsflag to generate minLength and maxLength attributes based on values in json and defaults to falsepickPopularFormatflag to pick popular format if more than one format existsaddFormatCountsflag to include counts by format for each key in data