can-query-logic/doc/prototype/is-member.md

query data

@function can-query-logic.prototype.isMember isMember
@parent can-query-logic.prototype

@description Return if a record belongs to a query.

@signature `queryLogic.isMember(query, record)`

  Used to tell if the `query` contains the instance object `record`.

  ```js
  import {QueryLogic} from "can";

  const queryLogic = new QueryLogic();

  const checkMember = queryLogic.isMember(
    {filter: {playerId: 5}},
    {id: 5, type: "3pt", playerId: 5, gameId: 7}
  );
  console.log( checkMember ); //-> true
  ```
  @codepen

  Use [can-query-logic.prototype.index] to know where to insert the `record` into a list of
  records.  

  `isMember` ignores the query's `page` values and will return `true` if the query's `filter` matches
  the data.  For example, "Zebra" might be the last record if all _animals_ were sorted by name. However,
  `isMember` will still return true:

  ```js
  import {QueryLogic} from "can";

  const animalQueryLogic = new QueryLogic();

  const checkAnimal = animalQueryLogic.isMember(
    {sort: "name", page: {start: 0, end: 0}},
    {id: 1, name: "Zebra"}
  );
  console.log( checkAnimal ); //-> true
  ```
  @codepen

  This is a limitation of QueryLogic when used with paginated sets of data.

  @param  {can-query-logic/query} set A set.
  @param  {Object} record A JavaScript object of key-value pairs.
  @return {Boolean} Returns `true` if `record` belongs in `set` and
   `false` it not.

@body

## Dealing with paginated sets

If you have paginated data, and you would like to build a real-time application that knows if some newly created
data belongs within that paginated set, you will need to build a custom real time [can-connect] behavior.

If you are encountering this problem, please post a question on the forums and Justin will detail how to solve this problem.