test.js

/** @satisfies {import('json-schema-to-ts').JSONSchema} */
const schema2 = {
  type: 'object',
  additionalProperties: false,
  properties: {
    input: {
      type: 'object',
      additionalProperties: false,
      properties: {
        x: { type: 'number' },
      },
    },
  },
}

/** @type {import('json-schema-to-ts').FromSchema<typeof schema2>} */
const value2 = {
  input: {
    x: 1,
  },
}
// const value2: {
//   input?: {
//       x?: number | undefined;
//   } | undefined;
// }
// @type — {import('json-schema-to-ts').FromSchema} Type

/** @satisfies {import('json-schema-to-ts').JSONSchema} */
const schemaRequired2 = {
  type: 'object',
  required: ['input'],
  additionalProperties: false,
  properties: {
    input: {
      type: 'object',
      additionalProperties: false,
      required: ['x'],
      properties: {
        x: { type: 'number' },
      },
    },
  },
}

/** @type {import('json-schema-to-ts').FromSchema<typeof schemaRequired2>} */
const valueRequired2 = {
  input: {
    x: 2,
  },
}
// Type '{ input: { x: number; }; }' is not assignable to type 'never'.ts(2322)
// const valueRequired2: never
// @type — {import('json-schema-to-ts').FromSchema}

console.log({ schema2, value2, schemaRequired2, valueRequired2 })

test2.ts

import { FromSchema, JSONSchema } from 'json-schema-to-ts'

const schema = {
  type: 'object',
  additionalProperties: false,
  properties: {
    input: {
      type: 'object',
      additionalProperties: false,
      properties: {
        x: { type: 'number' },
      },
    },
  },
} as const satisfies JSONSchema

type Schema = FromSchema<typeof schema>
// type Schema = {
//   input?: {
//       x?: number | undefined;
//   } | undefined;
// }
const value: Schema = {
  input: {
    x: 1,
  },
}
// const value: {
//   input?: {
//       x?: number | undefined;
//   } | undefined;
// }

const schemaRequired = {
  type: 'object',
  required: ['input'],
  additionalProperties: false,
  properties: {
    input: {
      type: 'object',
      additionalProperties: false,
      required: ['x'],
      properties: {
        x: { type: 'number' },
      },
    },
  },
} as const satisfies JSONSchema

type SchemaRequired = FromSchema<typeof schemaRequired>
// type SchemaRequired = {
//   input: {
//       x: number;
//   };
// }
const valueRequired: SchemaRequired = {
  input: {
    x: 1,
  },
}
// const valueRequired: {
//   input: {
//       x: number;
//   };
// }

console.log({ schema, value, schemaRequired, valueRequired })