omitBy

Creates a new object excluding the entries for which the predicate returns truthy. The predicate receives (value, key) for each own enumerable string property. Inverse of pickBy.

Try it

Import

import { omitBy } from "1o1-utils";

import { omitBy } from "1o1-utils/omit-by";

Signature

function omitBy<T extends Record<string, unknown>>({
  obj,
  predicate,
}: OmitByParams<T>): Partial<T>

Parameters

Name	Type	Required	Description
obj	Record<string, unknown>	Yes	The source object
predicate	(value, key) => boolean	Yes	Called per entry; the entry is removed when the function returns truthy

Returns

Partial<T> — A new object without the entries the predicate matched.

Examples

omitBy({ obj: { a: 1, b: 2, c: 3 }, predicate: (v) => v > 1 });
// => { a: 1 }

omitBy({
  obj: { id: 1, name: "Ada", password: "secret", token: "xyz" },
  predicate: (_, key) => key === "password" || key === "token",
});
// => { id: 1, name: "Ada" }

Edge Cases

• Throws if obj is not an object or is null.
• Throws if predicate is not a function.
• Prototype-pollution keys (__proto__, constructor, prototype) are skipped.
• Inherited keys are ignored — only own enumerable string keys are visited.

Also known as

filter object, exclude by value, conditional omit, predicate omit, reject

Prompt suggestion

I'm using 1o1-utils (npm: https://www.npmjs.com/package/1o1-utils, GitHub: https://github.com/pedrotroccoli/1o1-utils, LLM context: https://pedrotroccoli.github.io/1o1-utils/llms.txt). Show me how to use omitBy to strip secret fields from an object before logging it.