es-toolkit/compat

es-toolkit/compat mirrors Lodash's interface and behavior 1:1. It exists so you can lift an existing Lodash codebase into es-toolkit without rewriting call sites, and migrate to the strict API at your own pace.

If your project does not already use Lodash, please use es-toolkit instead.

::: tip ✅ 100% compatibility since v1.39.3 es-toolkit/compat passes Lodash's own test suite, so behavior is identical while staying lighter and faster. :::

// Same call signature as lodash, but coming from es-toolkit/compat
import { chunk } from 'es-toolkit/compat';

chunk([1, 2, 3, 4], 0);
// Returns [], identical to lodash

Migration flow

Recommended path for removing Lodash from an existing codebase:

1. Swap the import path from lodash / lodash-es to es-toolkit/compat. Leave call sites as they are.
2. Clean up call sites over time and switch the import to es-toolkit. Once done, you get a smaller bundle and faster runtime.

How it differs from es-toolkit

• API shape: matches Lodash 1:1, including implicit type coercions, multiple argument shapes, and deprecated helpers. es-toolkit only exposes the type-safe, modern forms.
• Bundle size and speed: slightly larger and slightly slower than es-toolkit, because it carries extra logic to match Lodash's behavior.
• Deprecated functions: kept in compat for parity, not in es-toolkit. Clean them up during migration.

For function-level documentation, see the Compat Reference.

Design Principles

::: info Design principles are subject to change. :::

Our compatibility layer aims to achieve feature parity with 100% accuracy for:

• Features that are written as a test case in lodash.
• Features that can be inferred from types of @types/lodash or @types/lodash-es.
• Feature differences identified while migrating code from lodash to es-toolkit (please report these to our issues page).

However, the following are out of scope for es-toolkit/compat:

• Implicit type conversions, such as converting an empty string to zero or false.
• Functions that have specialized implementations for specific types of arrays, like sortedUniq.
• Handling cases where internal object prototypes, like Array.prototype, have been modified.
• Managing cases with JavaScript realms.
• Method chaining: method chaining like _(arr).map(...).filter(...).

Implementation Status

::: info The following emojis indicate the status of each feature:

• ✅: Completed (The function is fully implemented and has passed all tests with lodash test code.)
• 📝: In Review (The function is implemented but hasn't been tested with lodash test code yet.)
• ❌: Not Implemented (The function hasn't been implemented.)

Even if a feature is marked "in review," it might already be under review to ensure it matches lodash perfectly, and it could already offer the same functionality. :::