omitBy()

omitBy<T>(object, predicate): Partial<T>

Creates an object composed of properties that predicate doesn't return truthy for.

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Type Parameters

T: T extends Record<string, unknown>

The type of the object.

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Parameters

object: T

The source object.

predicate: (value, key) => boolean

The function invoked per property.

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Returns: Partial<T>

A new object with filtered properties.

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See Also

pickBy

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Since

2.0.0

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Performance

O(n) where n is the number of own enumerable properties.

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Also known as

filter (Effect) · filterKey (Radashi) · omitBy (Lodash, es-toolkit, Remeda) · ❌ (Ramda, Modern Dash, Antfu)

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Example

const object = { a: 1, b: '2', c: 3 };

omitBy(object, value => typeof value === 'number');
// => { b: '2' }

// Remove null/undefined values
omitBy({ a: 1, b: null, c: undefined, d: 4 }, v => v == null);
// => { a: 1, d: 4 }

// Remove empty strings
omitBy({ name: 'John', email: '', phone: '123' }, v => v === '');
// => { name: 'John', phone: '123' }

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How it works?

Creates a new object excluding properties that satisfy a predicate.

Remove Null Values

Remove Empty Strings

pickBy vs omitBy

	pickBy	omitBy
Keeps if	predicate = true	predicate = false
Logic	Whitelist	Blacklist

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Use Cases

Remove Null/Undefined Values from objects 📌

Remove null and undefined values from objects. Essential for cleaning data before API calls.

#omit#filter#null#undefined#cleanup#filters

import { omitBy } from "@pithos/core/arkhe/object/omit-by";

const formData = {
  name: "John",
  email: "john@example.com",
  phone: null,
  address: undefined,
  age: 0,
  bio: "",
};

// Remove null and undefined values
const cleanData = omitBy(formData, (value) => value === null || value === undefined);
console.log(cleanData);
// { name: "John", email: "john@example.com", age: 0, bio: "" }

// Note: 0 and "" are preserved (only null/undefined removed)

Filter Sensitive Data before logging 📌

Remove sensitive fields from objects before logging. Critical for security compliance.

#sensitive#data#filter#logging#security#observability#filters

import { omitBy } from "@pithos/core/arkhe/object/omit-by";

const sensitiveKeys = new Set(["password", "token", "secret", "apiKey", "creditCard"]);

function sanitizeForLogging(data: Record<string, unknown>) {
  return omitBy(data, (_, key) => sensitiveKeys.has(key));
}

const userData = {
  id: "123",
  email: "user@example.com",
  password: "secret123",
  token: "jwt-token-here",
  preferences: { theme: "dark" },
};

console.log("User action:", sanitizeForLogging(userData));
// { id: "123", email: "user@example.com", preferences: { theme: "dark" } }

Remove Empty Values for query parameters

Filter out empty values when building query strings. Important for clean API requests.

#empty#values#query#parameters#URL#seo#filters

import { omitBy } from "@pithos/core/arkhe/object/omit-by";

function buildQueryString(params: Record<string, unknown>): string {
  // Remove empty values
  const cleanParams = omitBy(
    params,
    (value) => value === null || value === undefined || value === ""
  );

  return new URLSearchParams(
    Object.entries(cleanParams).map(([k, v]) => [k, String(v)])
  ).toString();
}

const searchParams = {
  query: "typescript",
  page: 1,
  limit: 10,
  category: "",
  author: null,
  sortBy: undefined,
};

const queryString = buildQueryString(searchParams);
console.log(queryString); // "query=typescript&page=1&limit=10"

Remove hidden columns from table render data

Strip hidden columns from row data before rendering to reduce DOM nodes. Essential for data tables with many optional columns.

#hidden#columns#table#render#data#design system#panels

const hiddenColumnKeys = new Set(["role", "lastLogin", "createdAt"]);

const visibleRowData = rows.map((row) =>
  omitBy(row, (_, key) => hiddenColumnKeys.has(key))
);

// Each row only contains visible column data
renderTableRows(visibleRowData);

Strip disabled features from a config

Remove disabled feature entries before passing config to the renderer. Essential for feature flag systems and conditional module loading.

#disabled#features#config#toggle#cleanup#filters#design system

const features = {
  darkMode: { enabled: true, version: "2.0" },
  betaSearch: { enabled: false, version: "0.1" },
  aiChat: { enabled: true, version: "1.5" },
  legacyNav: { enabled: false, version: "1.0" },
};

const activeFeatures = omitBy(features, (feature) => !feature.enabled);
// => { darkMode: {...}, aiChat: {...} }
loadModules(Object.keys(activeFeatures));