Source: https://tanstack.com/db/latest/docs/reference/functions/parseWhereExpression

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On this page

• Function: parseWhereExpression()

• Type Parameters

• T

• Parameters

• expr

• options

• Returns

• Examples

parseWhereExpression

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Function: parseWhereExpression()
================================

ts

function parseWhereExpression<T>(expr, options): T | null;


function parseWhereExpression<T>(expr, options): T | null;

Defined in: packages/db/src/query/expression-helpers.ts:201

Parses a WHERE expression into a custom format using provided handlers.

This is the main helper for converting TanStack DB where clauses into your API's filter format. You provide handlers for each operator, and this function traverses the expression tree and calls the appropriate handlers.

Type Parameters
--------------- ### T

T = any

Parameters
---------- ### expr

The WHERE expression to parse

BasicExpression<boolean> | null | undefined

### options

ParseWhereOptions <T>

Configuration with handler functions for each operator

Returns
-------

T | null

The parsed result in your custom format

Examples
--------

typescript

// REST API with query parameters
const filters = parseWhereExpression(where, {
  handlers: {
    eq: (field, value) => ({ [field.join('.')]: value }),
    lt: (field, value) => ({ [`${field.join('.')}_lt`]: value }),
    gt: (field, value) => ({ [`${field.join('.')}_gt`]: value }),
    and: (...filters) => Object.assign({}, ...filters),
    or: (...filters) => ({ $or: filters })
  }
})
// Returns: { category: 'electronics', price_lt: 100 }


// REST API with query parameters
const filters = parseWhereExpression(where, {
  handlers: {
    eq: (field, value) => ({ [field.join('.')]: value }),
    lt: (field, value) => ({ [`${field.join('.')}_lt`]: value }),
    gt: (field, value) => ({ [`${field.join('.')}_gt`]: value }),
    and: (...filters) => Object.assign({}, ...filters),
    or: (...filters) => ({ $or: filters })
  }
})
// Returns: { category: 'electronics', price_lt: 100 }

typescript

// GraphQL where clause
const where = parseWhereExpression(whereExpr, {
  handlers: {
    eq: (field, value) => ({ [field.join('_')]: { _eq: value } }),
    lt: (field, value) => ({ [field.join('_')]: { _lt: value } }),
    and: (...filters) => ({ _and: filters })
  }
})


// GraphQL where clause
const where = parseWhereExpression(whereExpr, {
  handlers: {
    eq: (field, value) => ({ [field.join('_')]: { _eq: value } }),
    lt: (field, value) => ({ [field.join('_')]: { _lt: value } }),
    and: (...filters) => ({ _and: filters })
  }
})

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