amp-has utility (re-export of lodash.has)

1.0.1 · deprecated · verified Wed Apr 22

The `amp-has` package provides a simple utility function, `has`, designed to check for the existence of nested properties within an object. It is part of the `ampersand.js` ecosystem, which was a collection of loosely coupled JavaScript modules for client-side applications. The package, currently at version 1.0.1, was last updated in April 2016 and is essentially a direct re-export of the `lodash.has` function. Given the minimal activity on the `ampersand.js` project and this specific utility's unmaintained status for many years, its release cadence is effectively ceased. Its key differentiator was its inclusion in the `ampersand.js` modular approach; however, modern applications are strongly advised to use `lodash.has` directly, which is actively maintained and supports contemporary JavaScript module systems.

Common errors

```
SyntaxError: Cannot use import statement outside a module
```
cause Attempting to use `import { has } from 'amp-has'` in a Node.js project that is configured as a CommonJS module or does not have `"type": "module"` in its `package.json`.

fix If staying with `amp-has`, use `const has = require('amp-has');`. Otherwise, migrate to `lodash.has` which offers better ESM support with modern tooling.
```
TypeError: has is not a function
```
cause This error can occur if you attempt to destructure `require('amp-has')` (e.g., `const { has } = require('amp-has')`) or use an incorrect `import` statement in a CJS context, as `amp-has` exports the `has` function directly as its `module.exports`.

fix The correct CommonJS import is `const has = require('amp-has');`.

Warnings

deprecated `amp-has` is unmaintained since 2016 and is merely a re-export of `lodash.has`. It is strongly recommended to switch directly to `lodash.has` to ensure you are using a current, maintained dependency and avoid potential compatibility issues.
Fix: Uninstall `amp-has` and install `lodash.has`. Replace `require('amp-has')` with `require('lodash.has')` or `import { has } from 'lodash';` if using a full Lodash build or ESM-compatible Lodash package.
gotcha This package is a CommonJS (CJS) module and does not natively support ES Module (ESM) `import` syntax. Attempting to use `import` statements will lead to runtime errors in pure ESM environments.
Fix: Ensure your project is configured for CommonJS, or use dynamic `import()` if you must use it in an ESM context, though switching to `lodash.has` (which supports ESM) is the better long-term solution. Example: `const has = await import('amp-has');` (note: this imports the module object, not the function directly).

Install

npm install amp-has npm
yarn add amp-has yarn
pnpm add amp-has pnpm

Imports

has
wrong:
```
import { has } from 'amp-has';
import has from 'amp-has';
```
correct:
```
const has = require('amp-has');
```
amp-has is a CommonJS module. It does not provide native ES Module exports. Attempting to use `import` syntax will result in errors.

Quickstart

Demonstrates importing and using the `has` function to safely check for the existence of nested properties within an object, including null or undefined paths.

const has = require('amp-has');

const user = {
  id: 1,
  name: 'Alice',
  address: {
    street: '123 Main St',
    city: 'Anytown',
    zip: '12345'
  },
  contact: null
};

console.log('User has address.city:', has(user, 'address.city'));
// Expected: true

console.log('User has address.country:', has(user, 'address.country'));
// Expected: false

console.log('User has id:', has(user, 'id'));
// Expected: true

console.log('User has contact.email:', has(user, 'contact.email'));
// Expected: false (handles null paths gracefully)

// For modern usage, it's recommended to use lodash.has directly:
// const lodashHas = require('lodash.has');
// console.log('Using lodash.has directly:', lodashHas(user, 'address.zip'));

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