Function applyOperation

src/core.ts:182–315

(document: T, operation: Operation, validateOperation: boolean | Validator<T> = false, mutateDocument: boolean = true, banPrototypeModifications: boolean = true, index: number = 0)

 * @return `{newDocument, result}` after the operation
 */
export function applyOperation<T>(document: T, operation: Operation, validateOperation: boolean | Validator<T> = false, mutateDocument: boolean = true, banPrototypeModifications: boolean = true, index: number = 0): OperationResult<T> {
  if (validateOperation) {
    if (typeof validateOperation == 'function') {
      validateOperation(operation, 0, document, operation.path);
    }
    else {
      validator(operation, 0);
    }
  }
  /* ROOT OPERATIONS */
  if (operation.path === "") {
    let returnValue: OperationResult<T> = { newDocument: document };
    if (operation.op === 'add') {
      returnValue.newDocument = operation.value;
      return returnValue;
    } else if (operation.op === 'replace') {
      returnValue.newDocument = operation.value;
      returnValue.removed = document; //document we removed
      return returnValue;
    }
    else if (operation.op === 'move' || operation.op === 'copy') { // it's a move or copy to root
      returnValue.newDocument = getValueByPointer(document, operation.from); // get the value by json-pointer in `from` field
      if (operation.op === 'move') { // report removed item
        returnValue.removed = document;
      }
      return returnValue;
    } else if (operation.op === 'test') {
      returnValue.test = _areEquals(document, operation.value);
      if (returnValue.test === false) {
        throw new JsonPatchError("Test operation failed", 'TEST_OPERATION_FAILED', index, operation, document);
      }
      returnValue.newDocument = document;
      return returnValue;
    } else if (operation.op === 'remove') { // a remove on root
      returnValue.removed = document;
      returnValue.newDocument = null;
      return returnValue;
    } else if (operation.op === '_get') {
      operation.value = document;
      return returnValue;
    } else { /* bad operation */
      if (validateOperation) {
        throw new JsonPatchError('Operation `op` property is not one of operations defined in RFC-6902', 'OPERATION_OP_INVALID', index, operation, document);
      } else {
        return returnValue;
      }
    }
  } /* END ROOT OPERATIONS */
  else {
    if (!mutateDocument) {
      document = _deepClone(document);
    }
    const path = operation.path || "";
    const keys = path.split('/');
    let obj = document;
    let t = 1; //skip empty element - http://jsperf.com/to-shift-or-not-to-shift
    let len = keys.length;
    let existingPathFragment = undefined;