CtrlK
BlogDocsLog inGet started
Tessl Logo

tessl/npm-lodash-reject

The lodash method reject exported as a module for filtering collections.

—

Pending
Quality

Pending

Does it follow best practices?

Impact

Pending

No eval scenarios have been run

SecuritybySnyk

Pending

The risk profile of this skill

Overview
Eval results
Files

Lodash Reject

The lodash.reject module provides the reject method from the lodash utility library as a standalone package. This method creates an array of elements that a predicate function returns falsy for, effectively filtering out elements that match the provided criteria.

Package Information

  • Package Name: lodash.reject
  • Package Type: npm
  • Language: JavaScript
  • Installation: npm install lodash.reject

Core Imports

const reject = require('lodash.reject');

ES6 module:

import reject from 'lodash.reject';

Basic Usage

const reject = require('lodash.reject');

const users = [
  { 'user': 'barney', 'age': 36, 'active': false },
  { 'user': 'fred',   'age': 40, 'active': true }
];

// Reject based on function predicate
const activeUsers = reject(users, function(o) { return !o.active; });
// => [{ 'user': 'fred', 'age': 40, 'active': true }]

// Reject using object predicate (matches properties)
const nonMatching = reject(users, { 'age': 40, 'active': true });
// => [{ 'user': 'barney', 'age': 36, 'active': false }]

// Reject using property-value pair predicate
const notInactive = reject(users, ['active', false]);
// => [{ 'user': 'fred', 'age': 40, 'active': true }]

// Reject using property name predicate
const inactive = reject(users, 'active');
// => [{ 'user': 'barney', 'age': 36, 'active': false }]

Capabilities

Reject Function

Creates an array of elements predicate returns falsy for. The opposite of _.filter; this method returns the elements of collection that predicate does NOT return truthy for.

/**
 * Creates an array of elements predicate returns falsy for.
 * @param {Array|Object} collection - The collection to iterate over.
 * @param {Function|Object|string} [predicate=_.identity] - The function invoked per iteration.
 * @returns {Array} Returns the new filtered array.
 */
function reject(collection, predicate);

Parameters:

  • collection (Array|Object): The collection to iterate over - can be an array or object
  • predicate (Function|Object|string, optional): The function invoked per iteration. Defaults to _.identity

Returns:

  • Array: Returns the new filtered array containing elements that do NOT match the predicate

Predicate Types:

  1. Function: function(value, index, collection) => boolean

    • Receives the current value, index/key, and collection
    • Return true to reject (exclude) the element

  2. Object: { property: value, ... }

    • Matches objects with the same property values (partial deep comparison)
    • Uses _.matches iteratee shorthand

  3. Array: [property, value]

    • Matches objects where object[property] === value
    • Uses _.matchesProperty iteratee shorthand

  4. String: 'property'

    • Matches objects where object[property] is truthy
    • Uses _.property iteratee shorthand

Usage Examples:

const reject = require('lodash.reject');

// Function predicate - reject active users
const users = [
  { name: 'Alice', active: true },
  { name: 'Bob', active: false },
  { name: 'Charlie', active: true }
];

const inactiveUsers = reject(users, user => user.active);
// => [{ name: 'Bob', active: false }]

// Object predicate - reject exact matches
const products = [
  { category: 'electronics', price: 100 },
  { category: 'books', price: 20 },
  { category: 'electronics', price: 200 }
];

const nonElectronics = reject(products, { category: 'electronics' });
// => [{ category: 'books', price: 20 }]

// Array predicate - reject by property-value pair
const items = [
  { type: 'urgent', priority: 1 },
  { type: 'normal', priority: 2 },
  { type: 'low', priority: 3 }
];

const nonUrgent = reject(items, ['type', 'urgent']);
// => [{ type: 'normal', priority: 2 }, { type: 'low', priority: 3 }]

// String predicate - reject by truthy property
const tasks = [
  { title: 'Task 1', completed: true },
  { title: 'Task 2', completed: false },
  { title: 'Task 3', completed: true }
];

const incompleteTasks = reject(tasks, 'completed');
// => [{ title: 'Task 2', completed: false }]

// With arrays of primitives
const numbers = [1, 2, 3, 4, 5, 6];
const evenNumbers = reject(numbers, n => n % 2 === 0);
// => [1, 3, 5]

// With objects (iterates over object values)
const scores = { alice: 85, bob: 92, charlie: 78 };
const belowNinety = reject(scores, score => score >= 90);
// => [85, 78]

Implementation Notes

  • Works with both arrays and objects (objects are iterated by their values)
  • Uses internal arrayFilter for arrays and baseFilter for objects
  • Predicate is normalized using getIteratee(predicate, 3) to handle different predicate types
  • Returns a new array; does not modify the original collection
  • For objects, the returned array contains the property values that don't match the predicate
  • Supports the same iteratee shorthands as other lodash methods (_.matches, _.matchesProperty, _.property)
Workspace
tessl
Visibility
Public
Created
Last updated
Describes
npmpkg:npm/lodash.reject@4.6.x
Publish Source
CLI
Badge
tessl/npm-lodash-reject badge