index.ts

export type JsonValue = JsonArray | JsonObject | boolean | null | number | string

export interface JsonArray extends Array<JsonValue> {}

export interface JsonObject {
  [key: string]: JsonValue
}

/**
 * Deep clone a JSON object or array. Only works for JSON objects and arrays.
 */
export const deepCloneJson = <T extends JsonObject>(inObject: T): T => {
  if (typeof inObject !== 'object' || inObject === null) {
    return inObject
  }

  const stack: { source: JsonArray | JsonObject; target: any }[] = [
    { source: inObject, target: Array.isArray(inObject) ? [] : {} },
  ]
  const root = stack[0].target

  while (stack.length > 0) {
    const { source, target } = stack.pop() as { source: JsonObject; target: any }

    for (const key in source) {
      const value = source[key]
      if (typeof value === 'object' && value !== null) {
        target[key] = Array.isArray(value) ? [] : {}
        stack.push({ source: value, target: target[key] })
      } else {
        target[key] = value
      }
    }
  }

  return root
}