compact

Creates a new object with all falsy values removed. Pass keep to preserve specific falsy values that should survive.

Try it

Falsy values are false, 0, -0, 0n, "", null, undefined, and NaN. Matches in keep use Object.is, so 0 vs -0 and NaN are handled exactly.

Import

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

import { compact } from "1o1-utils/compact";

Signature

function compact<T extends Record<string, unknown>>({ obj, keep }: CompactParams<T>): Partial<T>

Parameters

Name	Type	Required	Description
obj	T	Yes	The source object
keep	unknown[]	No	Falsy values to preserve (matched via Object.is)

Returns

Partial<T> — A new object without falsy entries (except those listed in keep).

Examples

compact({ obj: { a: 1, b: null, c: "", d: 0, e: false, f: "ok" } });
// => { a: 1, f: "ok" }

// Preserve specific falsy values
compact({ obj: { a: 0, b: null, c: "" }, keep: [0] });
// => { a: 0 }

// Match NaN exactly
compact({ obj: { a: NaN, b: 1 }, keep: [NaN] });
// => { a: NaN, b: 1 }

Edge Cases

• Throws if obj is not an object.
• Throws if obj is an array (use .filter(Boolean) instead).
• Throws if keep is provided but not an array.
• Skips unsafe keys (__proto__, constructor, prototype) to prevent prototype pollution.
• Symbol-keyed properties are ignored (only string-keyed enumerable own properties are processed).
• Truthy values inside keep are no-ops — keep is only useful for falsy values you want to preserve.
• Distinguishes 0 from -0 via Object.is.
• Does not mutate the original object.

Also known as

remove falsy, clean object, drop empty, prune null

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 compact to strip null/undefined fields from an object before serializing.