120 lines
4.8 KiB
Markdown
120 lines
4.8 KiB
Markdown
# @fastify/merge-json-schemas
|
|
|
|
[](https://github.com/fastify/merge-json-schemas/actions/workflows/ci.yml)
|
|
[](https://www.npmjs.com/package/@fastify/merge-json-schemas)
|
|
[](https://github.com/neostandard/neostandard)
|
|
|
|
__merge-json-schemas__ is a JavaScript library that builds a logical product (AND) for multiple [JSON schemas](https://json-schema.org/draft/2020-12/json-schema-core#name-introduction).
|
|
|
|
- [Installation](#installation)
|
|
- [Usage](#usage)
|
|
- [API](#api)
|
|
- [mergeSchemas(schemas, options)](#mergeschemasschemas-options)
|
|
- [resolvers](#resolvers)
|
|
- [defaultResolver](#defaultresolver)
|
|
- [License](#license)
|
|
|
|
<a name="installation"></a>
|
|
|
|
## Installation
|
|
|
|
```bash
|
|
npm i @fastify/merge-json-schemas
|
|
```
|
|
|
|
<a name="usage"></a>
|
|
|
|
## Usage
|
|
|
|
```javascript
|
|
const assert = require('node:assert')
|
|
const { mergeSchemas } = require('@fastify/merge-json-schemas');
|
|
|
|
const schema1 = {
|
|
$id: 'schema1',
|
|
type: 'object',
|
|
properties: {
|
|
foo: { type: 'string', enum: ['foo1', 'foo2'] },
|
|
bar: { type: 'string', minLength: 3 }
|
|
}
|
|
}
|
|
|
|
const schema2 = {
|
|
$id: 'schema1',
|
|
type: 'object',
|
|
properties: {
|
|
foo: { type: 'string', enum: ['foo1', 'foo3'] },
|
|
bar: { type: 'string', minLength: 5 }
|
|
},
|
|
required: ['foo']
|
|
}
|
|
|
|
const mergedSchema = mergeSchemas([schema1, schema2])
|
|
assert.deepStrictEqual(mergedSchema, {
|
|
$id: 'schema1',
|
|
type: 'object',
|
|
properties: {
|
|
foo: { type: 'string', enum: ['foo1'] },
|
|
bar: { type: 'string', minLength: 5 }
|
|
},
|
|
required: ['foo']
|
|
})
|
|
```
|
|
|
|
<a name="api"></a>
|
|
|
|
## API
|
|
|
|
<a name="merge-schemas"></a>
|
|
|
|
#### mergeSchemas(schemas, options)
|
|
|
|
Builds a logical conjunction (AND) of multiple [JSON schemas](https://json-schema.org/draft/2020-12/json-schema-core#name-introduction).
|
|
|
|
- `schemas` __\<objects[]\>__ - list of JSON schemas to merge
|
|
- `options` __\<object\>__ - optional options
|
|
- `resolvers` __\<object\>__ - custom resolvers for JSON schema keywords. Each key is the name of a JSON schema keyword. Each value is a resolver function. See [keywordResolver](#keywordresolver-keyword-values-mergedschema-parentschemas-options)
|
|
- `defaultResolver` __\<function\>__ - custom default resolver for JSON schema keywords. See [keywordResolver](#keywordresolver-keyword-values-mergedschema-parentschemas-options)
|
|
- `onConflict` __\<string\>__ - action to take when a conflict is found. Used by the default `defaultResolver`. Default is `throw`. Possible values are:
|
|
- `throw` - throws an error multiple different schemas for the same keyword are found
|
|
- `ignore` - do nothing if multiple different schemas for the same keyword are found
|
|
- `first` - use the value of the first schema if multiple different schemas for the same keyword are found
|
|
|
|
#### resolvers
|
|
|
|
A list of default resolvers that __merge-json-schema__ uses to merge JSON schemas. You can override the default resolvers by passing a list of custom resolvers in the `options` argument of `mergeSchemas`. See [keywordResolver](#keywordresolver-keyword-values-mergedschema-parentschemas-options).
|
|
|
|
#### defaultResolver
|
|
|
|
A default resolver that __merge-json-schema__ uses to merge JSON schemas. Default resolver is used when no custom resolver is defined for a JSON schema keyword. By default, the default resolver works as follows:
|
|
|
|
- If only one schema contains the keyword, the value of the keyword is used as the merged value
|
|
- If multiple schemas contain the exact same value for the keyword, the value of the keyword is used as the merged value
|
|
- If multiple schemas contain different values for the keyword, it throws an error
|
|
|
|
#### keywordResolver (keyword, values, mergedSchema, parentSchemas, options)
|
|
|
|
__merge-json-schema__ uses a set of resolvers to merge JSON schemas. Each resolver is associated with a JSON schema keyword. The resolver is called when the keyword is found in the schemas to merge. The resolver is called with the following arguments:
|
|
|
|
- `keyword` __\<string\>__ - the name of the keyword to merge
|
|
- `values` __\<any[]\>__ - the values of the keyword to merge. The length of the array is equal to the number of schemas to merge. If a schema does not contain the keyword, the value is `undefined`
|
|
- `mergedSchema` __\<object\>__ - an instance of the merged schema
|
|
- `parentSchemas` __\<object[]\>__ - the list of parent schemas
|
|
- `options` __\<object\>__ - the options passed to `mergeSchemas`
|
|
|
|
The resolver must set the merged value of the `keyword` in the `mergedSchema` object.
|
|
|
|
__Example:__ resolver for the `minNumber` keyword.
|
|
|
|
```javascript
|
|
function minNumberResolver (keyword, values, mergedSchema) {
|
|
mergedSchema[keyword] = Math.min(...values)
|
|
}
|
|
```
|
|
|
|
<a name="license"></a>
|
|
|
|
## License
|
|
|
|
Licensed under [MIT](./LICENSE).
|