A deep version of Ramda's whereEq and where (docs), allowing JSON-like declarative predicates for filtering functions etc.

Nested arrays and objects can be included in the spec. This allows the spec object to have the same shape (and to be a subset of) the test object, meaning you can just copy and trim its JSON representation to make a filter.

Values in the spec will be tested using ramda's equals (as with whereEq). By default, functions can also be included, as per where, and RegExp literals can be used to test values (as strings).

An options object allows overriding of default where... functions used with objects and arrays; and default equals functions used with values (strings, numbers, booleans and nulls).

Synopsis

// npm install where-deep
import * as R from 'ramda';
import {
  whereDeep, 
  arrayWhereAllUnordered, arrayWhereAllOrdered, 
  arrayWhereAny, arrayWhereWithReplacement
} from 'where-deep';
// import whereDeep from 'where-deep'; // default import 
const opts = {
  // arrayWhere: arrayWhereAllUnordered   
  // objectWhere: R.where    // R.whereAny also possible
  // stringEquals: R.equals  
  // numberEquals: R.equals
  // booleanEquals: R.equals
  // nullEquals: R.equals
  // errorHandler: e => false
  // allowFunctions: true
  // allowRegExp: true
};
const spec = {
  a: 1,
  c: [{d:4}] 
};
const testObj = {
  a: 1,
  b: 2,
  c: [{d:4, e:5},{d:"six"}]
};
whereDeep(opts, spec, testObj);  // true 
R.filter( whereDeep(opts, {c: [{d: "seven"}] }), [testObj] );  // []
R.filter( whereDeep(opts, {
  b: x => x>1,
  c: [ {d: /(six|seven)/i} ]
}), [testObj] );   // [testObj]

Examples

See test/examples.test.mjs

References

• Ramda where: https://ramdajs.com/docs/#where
• NPM: https://www.npmjs.com/package/where-deep