get-json-type

Does exactly what it says on the tin: generates a typescript type for any JSON input:

import { getJsonType } from "get-json-type";

console.log(getJsonType("hello world"));
// Output: 'string'

console.log(getJsonType([42, null]));
// Output: '(number | null)[]'

console.log(getJsonType({ foo: "bar", baz: [1, 2, 3] }));
// Output: '{ foo: string; baz: number[] }'

getJsonType also accepts an optional second argument for options:

getJsonType({ foo: "bar", baz: [1, 2, 3] }, {
    multiline: true,
    indentSize: 2,
    typeName: "MyType"
})
// Output:
// type MyType = {
//   foo: string;
//   baz: number[];
// }

Options

All options are optional. The available options are:

Option	type	default	description
multiline	boolean	false	If true, formats the output type with newlines and indentation.
indentSize	number	2	Number of spaces to use for indentation when multiline is true.
typeName	string	undefined	If provided, wraps the output type in a type alias with the given name.
throwOnUnknown	boolean	false	If true, throws an error when encountering a value that isn't valid JSON (e.g., functions, symbols). If false, these values are represented as any.
useLiteralTypes	boolean	false	If true, uses literal types for string, number, and boolean values (e.g., "hello" instead of string, 42 instead of number).

Development

To build the project, run:

pnpm build

To run tests, use:

pnpm test