@loopback/docs

--- lang: en title: 'API docs: filter' keywords: LoopBack 4.0, LoopBack 4, Node.js, TypeScript, OpenAPI sidebar: lb4_sidebar editurl: https://github.com/loopbackio/loopback-next/tree/master/packages/filter permalink: /doc/en/lb4/apidocs.filter.html ---  [Home](./index.md) > [@loopback/filter](./filter.md) ## filter package A set of utility typings and filter builders to aid in constructing LoopBack filters using the [builder pattern](https://en.wikipedia.org/wiki/Builder_pattern). ## Remarks This lightweight module provides strongly-typed typings and filter builders to intuitively construct LoopBack filters to be used against querying a LoopBack filter-compatible server over the network or within the server itself. ## Classes <table><thead><tr><th> Class </th><th> Description </th></tr></thead> <tbody><tr><td markdown="1"> [FilterBuilder](./filter.filterbuilder.md) </td><td markdown="1"> A builder for Filter. It provides fleunt APIs to add clauses such as `fields`, `order`, `where`, `limit`, `offset`, and `include`. </td></tr> <tr><td markdown="1"> [WhereBuilder](./filter.wherebuilder.md) </td><td markdown="1"> A builder for Where object. It provides fluent APIs to add clauses such as `and`, `or`, and other operators. </td></tr> </tbody></table> ## Functions <table><thead><tr><th> Function </th><th> Description </th></tr></thead> <tbody><tr><td markdown="1"> [filterTemplate(strings, keys)](./filter.filtertemplate.md) </td><td markdown="1"> </td></tr> <tr><td markdown="1"> [isFilter(candidate)](./filter.isfilter.md) </td><td markdown="1"> TypeGuard for Filter </td></tr> </tbody></table> ## Interfaces <table><thead><tr><th> Interface </th><th> Description </th></tr></thead> <tbody><tr><td markdown="1"> [AndClause](./filter.andclause.md) </td><td markdown="1"> And clause </td></tr> <tr><td markdown="1"> [Filter](./filter.filter.md) </td><td markdown="1"> Query filter object </td></tr> <tr><td markdown="1"> [Inclusion](./filter.inclusion.md) </td><td markdown="1"> Inclusion of related items Note: scope means filter on related items Example: `{relation: 'aRelationName', scope: {<AFilterObject>}}` </td></tr> <tr><td markdown="1"> [OrClause](./filter.orclause.md) </td><td markdown="1"> Or clause </td></tr> </tbody></table> ## Type Aliases <table><thead><tr><th> Type Alias </th><th> Description </th></tr></thead> <tbody><tr><td markdown="1"> [Condition](./filter.condition.md) </td><td markdown="1"> Condition clause </td></tr> <tr><td markdown="1"> [Direction](./filter.direction.md) </td><td markdown="1"> Order by direction </td></tr> <tr><td markdown="1"> [Fields](./filter.fields.md) </td><td markdown="1"> Selection of fields Example: `{afieldname: true}` </td></tr> <tr><td markdown="1"> [FilterExcludingWhere](./filter.filterexcludingwhere.md) </td><td markdown="1"> Filter without `where` property </td></tr> <tr><td markdown="1"> [InclusionFilter](./filter.inclusionfilter.md) </td><td markdown="1"> Inclusion filter type e.g. 'property', {relation: 'property'} </td></tr> <tr><td markdown="1"> [KeyOf](./filter.keyof.md) </td><td markdown="1"> Key types of a given model, excluding operators </td></tr> <tr><td markdown="1"> [Operators](./filter.operators.md) </td><td markdown="1"> Operators for where clauses </td></tr> <tr><td markdown="1"> [Order](./filter.order.md) </td><td markdown="1"> Order by Example: `{afieldname: 'ASC'}` </td></tr> <tr><td markdown="1"> [PredicateComparison](./filter.predicatecomparison.md) </td><td markdown="1"> Matching predicate comparison </td></tr> <tr><td markdown="1"> [ShortHandEqualType](./filter.shorthandequaltype.md) </td><td markdown="1"> Value types for `{propertyName: value}` </td></tr> <tr><td markdown="1"> [Where](./filter.where.md) </td><td markdown="1"> Where clause </td></tr> </tbody></table>