Ampersand.js Each Utility

Common errors

• ReferenceError: require is not defined

  cause Attempting to use `require('amp-each')` in a JavaScript file that is being interpreted as an ES module (e.g., due to `"type": "module"` in `package.json` or a `.mjs` extension).
  fix Change the file to a CommonJS module (e.g., rename to `.cjs`, remove `"type": "module"` from `package.json`, or configure your build system). Alternatively, use a dynamic import (`import('amp-each').then(mod => mod)`), though this package is not designed for it.

• TypeError: (0 , amp_each_1.default) is not a function

  cause Incorrect ES module import (`import each from 'amp-each'`) for a CommonJS module that exports a single function directly (not as a default object property).
  fix If transpilation is in place, try `import * as each from 'amp-each';` and then use `each.default(collection, fn)`. However, the recommended fix is to revert to `const each = require('amp-each');`.

• TypeError: each is not a function

  cause The `amp-each` module was imported incorrectly, or the variable `each` was not assigned the exported function. This can happen with incorrect `require()` syntax or failed ES module imports.
  fix Ensure the import is `const each = require('amp-each');` for CommonJS, or verify your bundler's configuration if using ES modules in a browser context.

Warnings

• breaking The entire ampersand.js project, including `amp-each`, appears to be abandoned. It has not seen updates in many years and lacks active maintenance, posing risks for security and compatibility with modern environments.
  Fix: Consider replacing with native JavaScript methods (e.g., `Array.prototype.forEach`, `Object.keys().forEach`) or a actively maintained utility library like Lodash (`_.each`).
• gotcha This package is exclusively a CommonJS (CJS) module. Attempting to use ES module `import` syntax will result in runtime errors in environments that don't specifically transpile CJS to ESM.
  Fix: Ensure you use `const each = require('amp-each');` for Node.js environments or configure your bundler (e.g., Webpack, Rollup) to handle CJS modules if targeting browsers.
• gotcha Modern JavaScript environments provide native iteration alternatives (e.g., `Array.prototype.forEach`, `Object.keys().forEach`, `for...of` loops) that offer similar functionality, often with better performance and native support, making this package largely redundant in current development.
  Fix: Prefer native JavaScript iteration methods for better maintainability, performance, and reduced bundle size.
• gotcha The package does not ship with TypeScript definitions. Using it in a TypeScript project will require manual type declarations or using `any`, leading to a loss of type safety.
  Fix: If you must use this library, install `@types/amp-each` if available (unlikely due to abandonment) or create a custom declaration file (e.g., `amp-each.d.ts`) to provide type information.

Install

• npm install amp-each npm
• yarn add amp-each yarn
• pnpm add amp-each pnpm

Imports

• each
  wrong:

  import each from 'amp-each';

  correct:

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

  This package is a CommonJS module and does not natively support ES module import syntax. Use `require()` in Node.js or a bundler for browser usage.

Quickstart

Demonstrates how to use `amp-each` to iterate over arrays and objects, applying a callback function to each element or property, and passing a context object.

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

// Example 1: Iterating over an array
const numbers = [1, 2, 3, 4, 5];
const doubledNumbers = [];

each(numbers, function (num, index) {
  doubledNumbers.push(num * 2);
  console.log(`Array item at index ${index}: ${num}`);
});
console.log('Doubled Numbers:', doubledNumbers);

// Example 2: Iterating over an object
const user = {
  name: 'Alice',
  age: 30,
  city: 'New York'
};

console.log('\nUser details:');
each(user, function (value, key) {
  console.log(`${key}: ${value}`);
});

// Example 3: Using 'this' context (if the function supports it, which 'amp-each' typically would)
const contextObject = { multiplier: 10 };
const multipliedNumbers = [];

each(numbers, function (num) {
  multipliedNumbers.push(num * this.multiplier);
}, contextObject);
console.log('Multiplied by context:', multipliedNumbers);