minimal-schema
v1.0.2
Published
Generate minimal placeholder data from JSON Schemas
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minimal-schema
This package is fork of empty-schema package, which is fork of json-schema-empty
Difference:
- introduces
format
support for strings, which means that generated data is valid against its JSON Schema; - supports
prefixItems
tuples; - contains minimal typescript typings: quite simple for now, but better than nothing.
Generate empty placeholder data from JSON Schemas
Generating random data is useful for testing (try out JSON Schema Faker or hazy if you have this need), but developers often require empty placeholder data to work with, particularly when developing web forms.
Data that minimal-schema
generates conforms to the following:
- Data is generated deterministically. If the schema is the same, the data will be the same. Exception is
string
type with date and time relatedformat
keyword: in this casenew Date().toISOString()
data is used. - Data is as simple as possible.
- Data conforms to the form specified in the schema. It will, however, sometimes fail to be valid according to the schema. The reason for this is simple: you cannot generate all values automatically (see the rules section for more info on this).
Installation
npm install --save minimal-schema
Usage
import {minimal} from 'minimal-schema'
const schema = {
type: 'object',
properties: {
foo: {
type: 'integer',
minimum: 12,
multipleOf: 5
},
bar: {
type: 'array',
items: { type: 'integer' },
minItems: 3
},
baz: {
type: 'string',
minLength: 5
},
email: {
type: 'string',
format: 'email'
},
dateTime: {
type: 'string',
format: 'date-time'
}
},
required: [ 'foo', 'bar', 'baz', 'email', 'dateTime' ]
}
console.log(empty(schema))
// {
// foo: 15,
// bar: [ 0, 0, 0 ],
// baz: '',
// email: 'a@a',
// dateTime: '2020-07-30T08:30:55.797Z'
// }
Rules
string: except when
format
keyword is present, it impossible to guess what the string content should be, even when patterns and length limits are given, a string schema always results in the empty string:''
. . Original behavior is inherited fromjson-schema-empty
.integer:
minimal-schema
tries to satisfy theminimum
,maximum
andmultipleOf
constraints whenever possible with the additional property that, when it is possible,0
is returned.number: just follows the
integer
schema.object: tries to create a minimal object with as few keys as possible. Only keys that are in the
required
array are generated.Object size is ignored completely, for the same reason that the strings are empty: we cannot guess the keys.
array:
- when the
item
type is given, andminItems
is given, the shortest array that matches this is generated; - supports
prefixItems
anditems
is a tuple; maxItems
is ignored;- whenever possible, the empty array is returned.
- when the
boolean: always results in
false
.null: always results in
null
.oneOf, anyOf: selects one of the accepted types and goes from there.
allOf:
minimal-schema
merges all schemas and works from that schema to generate a value.enum: selects the first possible value.
$ref
: just works!
Whenever specified, minimal-schema
uses the default
value (even if it
does not match the schema).
TODO
- [ ] Create options: custom defaults and settings for each type
License
This code is licensed under the ISC License