grafana/public/app/features/variables/guard.ts

import {
  AdHocVariableModel,
  ConstantVariableModel,
  QueryVariableModel,
  VariableModel,
  VariableWithMultiSupport,
} from './types';

export const isQuery = (model: VariableModel): model is QueryVariableModel => {
  return model.type === 'query';
};

export const isAdHoc = (model: VariableModel): model is AdHocVariableModel => {
  return model.type === 'adhoc';
};

export const isConstant = (model: VariableModel): model is ConstantVariableModel => {
  return model.type === 'constant';
};

export const isMulti = (model: VariableModel): model is VariableWithMultiSupport => {
  const withMulti = model as VariableWithMultiSupport;
  return withMulti.hasOwnProperty('multi') && typeof withMulti.multi === 'boolean';
};