Prototype Inheritance Utility

0.0.3 · abandoned · verified Sun Apr 19

The `component-inherit` package is a minimalist utility designed for establishing prototype inheritance in JavaScript. Released at a very early stage (current version 0.0.3), it was part of the now-defunct `component.io` ecosystem, as indicated by its `component install` instruction in the README. Its primary function, demonstrated through a simple `inherit(Child, Parent)` pattern, is to link prototypes, effectively achieving what `Child.prototype = Object.create(Parent.prototype)` or, more recently, `class Child extends Parent {}` accomplish natively in modern JavaScript. The package is effectively abandoned, given its very low version number, lack of updates, and reliance on an archaic module system (CommonJS) and installation method (component.io) that predates widespread npm adoption and native ES modules. It has no active release cadence and its utility has been entirely superseded by native language features.

Common errors

```
TypeError: Cannot read properties of undefined (reading 'call')
```
cause Attempting to use `inherit` without correctly calling the parent constructor to initialize instance properties within the child constructor.

fix Ensure that within your child constructor, you explicitly call the parent constructor using `Parent.call(this, ...args);` before any child-specific initialization.
```
SyntaxError: Named export 'inherit' not found. The requested module 'inherit' does not provide an export named 'inherit'
```
cause Attempting to import `inherit` using ES module named import syntax (`import { inherit } from 'inherit';`) when it is a CommonJS module that exports a default function.

fix Use CommonJS `require` syntax: `const inherit = require('inherit');`.

Warnings

deprecated The `component-inherit` package is entirely superseded by native JavaScript features (e.g., `class extends`, `Object.setPrototypeOf`, or manual prototype assignment with `Object.create`). It should not be used in modern JavaScript development.
Fix: Rewrite your code to use `class extends Parent {}` syntax for ES6+ or `Child.prototype = Object.create(Parent.prototype)` for older environments. If calling the parent constructor, use `Parent.call(this, ...args)`.
gotcha This package relies on the `component.io` installation method (`component install`), which is obsolete. It is available on npm but is not maintained for modern environments.
Fix: Avoid using this package. If you must, ensure your project's tooling can handle CommonJS modules from npm, but be aware of its age and lack of support.
gotcha The package is a pure CommonJS module and does not provide ES module exports. Attempting to `import` it will result in errors in native ESM environments or bundling issues.
Fix: Do not attempt to `import` this module. If using a bundler, ensure it can transpile CommonJS `require` statements. Prefer modern native solutions instead.
gotcha This package offers no type definitions for TypeScript. Using it in a TypeScript project will require manual declaration files or `// @ts-ignore` directives, further indicating its obsolescence.
Fix: Avoid using in TypeScript. If absolutely necessary, create a `declare module 'inherit';` declaration file.

Install

npm install component-inherit npm
yarn add component-inherit yarn
pnpm add component-inherit pnpm

Imports

inherit
wrong:
```
import inherit from 'inherit';
```
correct:
```
const inherit = require('inherit');
```
This package is a legacy CommonJS module from the component.io ecosystem and does not support ES modules. Direct `require` is the only functional import method.
default import
wrong:
```
import { inherit } from 'inherit';
```
correct:
```
N/A
```
There is no named export for this module; it exports a single function as its module.exports object.

Quickstart

Demonstrates how to use `component-inherit` to establish a prototype chain between two constructor functions in a CommonJS environment.

const inherit = require('inherit');

// Define a base constructor function (the parent)
function Human(name) {
  this.name = name;
}
Human.prototype.greet = function() {
  return `Hello, my name is ${this.name}`;
};

// Define a derived constructor function (the child)
function Woman(name, age) {
  Human.call(this, name); // Call parent constructor for inherited properties
  this.age = age;
}

// Establish prototype chain using component-inherit
inherit(Woman, Human);

// Add Woman-specific methods to its prototype
Woman.prototype.identify = function() {
  return `${this.greet()} and I am ${this.age} years old.`;
};

// Example usage
const alice = new Woman('Alice', 30);
console.log(alice.greet());
console.log(alice.identify());

// Verify instanceof chain
console.log(alice instanceof Woman); // true
console.log(alice instanceof Human); // true
console.log(Object.getPrototypeOf(Woman.prototype) === Human.prototype); // true

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