realm-query-builder

Is a powerful query builder for Realm.js, designed to simplify and enhance the querying experience for your Realm databases.

Immutable: All API operations that change the realm-query-builder object will return a new instance instead.

Installation

npm install --save realm-query-builder
# or
yarn add realm-query-builder

Useful Links

Some useful links for understanding and working with Realm queries:

• Realm Query Language (Comprehensive)
• Realm Query Language API (API-specific)

These resources provide in-depth information on Realm query language and its usage, helping you make the most out of realm-query-builder.

Example

Using realmQueryBuilder directly

import realmQueryBuilder from 'realm-query-builder';

const users = realmQueryBuilder(realm.objects('User'))
  .equalTo('active', true)
  .greaterThanOrEqualTo('age', 18)
  .in('country', ['BR', 'AR', 'US'])
  .distinct('name')
  .result();

console.log(users);

Extending

import { RealmQueryBuilder } from 'realm-query-builder';

type User = {
  age: number,
  active: boolean,
}

class UserQuery extends RealmQueryBuilder<User & Realm.Object> {
  active() {
    return this.equalTo('active', true);
  }

  byAge(age: number) {
    return this.equalTo('age', age);
  }
}

const userQuery = () => new UserQuery(realm.objects<User>('User'));

const users = userQuery()
  .active()
  .byAge(18)
  .distinct('country')
  .result();

console.log(users);

API

where(field: string, condition: RealmConditionalOperator, value: any): this

Adds a filter to the query with the specified property, operator and value.

equalTo(field: string, value: any, caseInsensitive?: boolean): this

Filter the data by property that match a specified value.

notEqualTo(field: string, value: any, caseInsensitive?: boolean): this

Evaluates to true expression matches property value wildcard string expression. A wildcard string expression is a string that uses normal characters with two special wildcard characters:

• The * wildcard matches zero or more of any character.
• The ? wildcard matches any character.

For example, the wildcard string d?g matches dog, dig, and dug, but not ding, dg, or a dog.

like(field: string, value: string, caseInsensitive?: boolean): this

An alias for where(field, 'LIKE' | 'LIKE[c]', value). If caseInsensitive: true, the operator applied will be LIKE[c].

contains(field: string, value: string, caseInsensitive?: boolean): this

An alias for where(field, 'CONTAINS' | 'CONTAINS[c]', value). If caseInsensitive: true, the operator applied will be CONTAINS[c].

beginsWith(field: string, value: string, caseInsensitive?: boolean): this

An alias for where(field, 'BEGINSWITH' | BEGINSWITH[c], value). If caseInsensitive, true the operator applied will be BEGINSWITH[c].

endsWith(field: string, value: string, caseInsensitive?: boolean): this

An alias for where(field, 'ENDSWITH' | ENDSWITH[c], value). If caseInsensitive: true, the operator applied will be ENDSWITH[c].

greaterThan(field: string, value: RealmNumericValueType): this

An alias for where(field, '>', value).

greaterThanOrEqualTo(field: string, value: RealmNumericValueType): this

An alias for where(field, '>=', value).

lessThan(field: string, value: RealmNumericValueType): this

An alias for where(field, '<', value).

lessThanOrEqualTo(field: string, value: RealmNumericValueType): this

An alias for where(field, '<=', value).

between(field: string, start: RealmNumericValueType, end: RealmNumericValueType): this

A between condition, same as:

realmQueryBuilder(object)
  .beginGroup()
    .where(field, '>=', start)
    .where(field, '<=', end)
  .endGroup();

or(): this

Join previous and next conditions with the OR operator.

and(): this

Join previous and next conditions with the AND operator, the default operator is AND.

beginGroup(): this

Begins a group for combining filter conditions in the query. Use with endGroup() to close the group.

endGroup(): this

Ends a group for combining filter conditions in the query. Should be used after starting a group with beginGroup().

Example:

realmQueryBuilder(realm.objects('User'))
  .equalTo('active', true)
  .beginGroup()
    .equalTo('canWrite', true)
    .or()
    .equalTo('admin', true)
  .endGroup()
  .result();

in(field: string, values: ReadonlyArray<any>): this

Adds an IN filter condition to the query, filtering objects where the specified property's value matches any of the values in the provided array. Realm.js started supporting IN in version 10.20.0, it is applied with OR chains for more compatibility.

not(): this

Implements not operator for the next operation or group.

distinct(...fields: string[]): this

Add DISTINCT suffix, see: Realm Query Language

sorted(field: string, order?: RealmQuerySort): this

Call the sorted method, see: sorted

limit(limit: number): this

Add LIMIT suffix, see: Realm Query Language

clone(): this

Create a clone of the current object.

truepredicate(): this

A predicate that always evaluates to TRUE.

falsepredicate(): this

A predicate that always evaluates to FALSE.

merge(query: RealmQueryBuilder<T>)): this

Merges the current query with another RealmQueryBuilder instance.

The operators sorted and limit are not merged.

Example:

const queryA =  realmQueryBuilder(realm.objects('User'))
  .equalTo('active', true)
  .equalTo('admin', false)
  .limit(10);

const queryB =  realmQueryBuilder(realm.objects('User'))
  .greaterThanOrEqualTo('age', 18)
  .limit(20)
  .or()
  .beginGroup()
    .merge(queryA)
  .endGroup()
  .result();

min<V extends RealmNumericValueType>(property?: string): V | null

Call realm.js min

max<V extends RealmNumericValueType>(property?: string): V | null

Call realm.js max

sum(property?: string): number | null

Call realm.js sum

avg(property?: string): number

Call realm.js avg

first(): T | undefined

Get the first result.

last(): T | undefined

Get the last result.

findBy(field: string, value: any): T | undefined

Apply the where(field, '==', value) condition and return the first value.

size(): number

Query the data and get the result's size, alias to result().length

result(): Realm.Results<T>

Executes the query and returns the filtered results