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Compile JSON Schema to TypeScript typings.

Check out thelive demo.

Input:

{"title":"Example Schema","type":"object","properties": {"firstName": {"type":"string"    },"lastName": {"type":"string"    },"age": {"description":"Age in years","type":"integer","minimum":0    },"hairColor": {"enum": ["black","brown","blue"],"type":"string"    }  },"additionalProperties":false,"required": ["firstName","lastName"]}

Output:

exportinterfaceExampleSchema{firstName:string;lastName:string;/**   * Age in years   */age?:number;hairColor?:"black"|"brown"|"blue";}

npm install json-schema-to-typescript

json-schema-to-typescript is easy to use via the CLI, or programmatically.

First make the CLI available using one of the following options:

# install locally, then use `npx json2ts`npm install json-schema-to-typescript# or install globally, then use `json2ts`npm install json-schema-to-typescript --global# or install to npm cache, then use `npx --package=json-schema-to-typescript json2ts`# (you don't need to run an install command first)

Then, use the CLI to convert JSON files to TypeScript typings:

cat foo.json| json2ts> foo.d.ts# orjson2ts foo.json> foo.d.ts# orjson2ts foo.yaml foo.d.ts# orjson2ts --input foo.json --output foo.d.ts# orjson2ts -i foo.json -o foo.d.ts# or (quote globs so that your shell doesn't expand them)json2ts -i'schemas/**/*.json'# orjson2ts -i schemas/ -o types/

You can pass any of the options described below (including style options) as CLI flags. Boolean values can be set to false using theno- prefix.

# generate code for definitions that aren't referencedjson2ts -i foo.json -o foo.d.ts --unreachableDefinitions# use single quotes and disable trailing semicolonsjson2ts -i foo.json -o foo.d.ts --style.singleQuote --no-style.semi

To invoke json-schema-to-typescript from your TypeScript or JavaScript program, import it and callcompile orcompileFromFile.

import{compile,compileFromFile}from'json-schema-to-typescript'// compile from filecompileFromFile('foo.json').then(ts=>fs.writeFileSync('foo.d.ts',ts))// or, compile a JS objectletmySchema={properties:[...]}compile(mySchema,'MySchema').then(ts=> ...)

Seeserver demo andbrowser demo for full examples.

compileFromFile andcompile accept options as their last argument (all keys are optional):

$ npmtest

• title =>interface
• Primitive types:
  • array
  • homogeneous array
  • boolean
  • integer
  • number
  • null
  • object
  • string
  • homogeneous enum
  • heterogeneous enum
• Non/extensible interfaces
• Custom JSON-schema extensions
• Nested properties
• Schema definitions
• Schema references
• Local (filesystem) schema references
• External (network) schema references
• Add support for running in browser
• default interface name
• infer unnamed interface name from filename
• deprecated
• allOf ("intersection")
• anyOf ("union")
• oneOf (treated likeanyOf)
• maxItems (eg)
• minItems (eg)
• additionalProperties of type
• patternProperties (partial support)
• extends
• required properties on objects (eg)
• validateRequired (eg)
• literal objects in enum (eg)
• referencing schema by id (eg)
• custom typescript types viatsType

• tsType: Overrides the type that's generated from the schema. Useful for forcing a type toany or when using non-standard JSON schema extensions (eg).
• tsEnumNames: Overrides the names used for the elements in an enum. Can also be used to create string enums (eg).

• dependencies (single,multiple)
• divisibleBy (eg)
• format (eg)
• multipleOf (eg)
• maximum (eg)
• minimum (eg)
• maxProperties (eg)
• minProperties (eg)
• not/disallow
• oneOf ("xor", useanyOf instead)
• pattern (string,regex)
• uniqueItems (eg)

Prettier is known to run slowly on really big files. To skip formatting and improve performance, set theformat option tofalse.

• JSON-schema spec:https://tools.ietf.org/html/draft-zyp-json-schema-04
• JSON-schema wiki:https://github.com/json-schema/json-schema/wiki
• JSON-schema test suite:https://github.com/json-schema/JSON-Schema-Test-Suite/blob/node
• TypeScript spec:https://github.com/Microsoft/TypeScript/blob/master/doc/spec.md

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