jsonbinpack/lib/json.ts

A space-efficient schema-driven binary JSON serialization format based on JSON Schema

/*
 * Copyright 2021 Juan Cruz Viotti
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

export type JSONNumber = number
export type JSONBoolean = boolean
export type JSONString = string
export type JSONNull = null

export type JSONScalar = JSONNumber | JSONBoolean | JSONString | JSONNull

export interface JSONObject {
  // eslint-disable-next-line no-use-before-define
  readonly [key: string]: JSONValue;
}

export type JSONValue =
  JSONObject | JSONValue[] | JSONScalar

// As documented in https://www.json.org
export enum JSONType {
  number = 'number',
  boolean = 'boolean',
  string = 'string',
  null = 'null',
  object = 'object',
  array = 'array'
}

export enum JSONTypeCategory {
  numeric = 'numeric',
  textual = 'textual',
  boolean = 'boolean',
  structural = 'structural'
}

export const getJSONType = (value: JSONValue): JSONType => {
  if (typeof value === 'boolean') {
    return JSONType.boolean
  } else if (typeof value === 'number') {
    return JSONType.number
  } else if (typeof value === 'string') {
    return JSONType.string
  } else if (Array.isArray(value)) {
    return JSONType.array
  } else if (value === null) {
    return JSONType.null
  }

  return JSONType.object
}

export const getJSONTypeCategory = (type: JSONType): JSONTypeCategory => {
  if (type === JSONType.boolean || type === JSONType.null) {
    return JSONTypeCategory.boolean
  } else if (type === JSONType.string) {
    return JSONTypeCategory.textual
  } else if (type === JSONType.number) {
    return JSONTypeCategory.numeric
  }

  return JSONTypeCategory.structural
}

export const getJSONSize = (document: JSONValue): number => {
  return Buffer.byteLength(JSON.stringify(document), 'utf8')
}