### Initial Project Setup

Source: https://github.com/endojs/endo/blob/master/CONTRIBUTING.md

Clone the repository, navigate to the directory, and install dependencies using yarn. This is the first step for any contributor.

```sh
git clone git@github.com:endojs/endo.git
cd endo
yarn
```

--------------------------------

### Install @endo/memoize with yarn

Source: https://github.com/endojs/endo/blob/master/packages/memoize/README.md

Install the @endo/memoize package using yarn.

```sh
yarn add @endo/memoize
```

--------------------------------

### Install @endo/lp32 with npm

Source: https://github.com/endojs/endo/blob/master/packages/lp32/README.md

Installs the @endo/lp32 package using npm.

```sh
npm install @endo/lp32
```

--------------------------------

### Install Endo CLI from Source

Source: https://github.com/endojs/endo/blob/master/packages/cli/demo/README.md

Clone the Endo repository, install dependencies with Yarn, and create an alias for the Endo command.

```bash
> git clone https://github.com/endojs/endo.git
> yarn
> alias endo=$PWD/packages/cli/bin/endo.cjs
```

--------------------------------

### Install Endo Dependencies

Source: https://github.com/endojs/endo/blob/master/docs/get-started.md

Installs necessary packages for demonstrating CapTP locally, including initialization, CapTP protocol, stream utilities, eventual send, exo, and patterns.

```bash
npm install @endo/init
npm install @endo/captp
npm install @endo/stream
npm install @endo/eventual-send
npm install @endo/exo
npm install @endo/patterns
```

--------------------------------

### Install @endo/lp32 with yarn

Source: https://github.com/endojs/endo/blob/master/packages/lp32/README.md

Installs the @endo/lp32 package using yarn.

```sh
yarn add @endo/lp32
```

--------------------------------

### Install ESLint

Source: https://github.com/endojs/endo/blob/master/packages/eslint-plugin/README.md

Install ESLint as a development dependency for your project.

```sh
npm i eslint --save-dev
```

--------------------------------

### Install @endo/memoize with npm

Source: https://github.com/endojs/endo/blob/master/packages/memoize/README.md

Install the @endo/memoize package using npm.

```sh
npm install @endo/memoize
```

--------------------------------

### Basic Usage Example

Source: https://github.com/endojs/endo/blob/master/packages/promise-kit/README.md

Demonstrates the basic usage of `makePromiseKit` to create a promise that is resolved or rejected after a delay.

```APIDOC
## Basic Usage of makePromiseKit

### Description
This example shows how to use `makePromiseKit` to create a promise for an asynchronous operation. The promise is resolved or rejected based on a simulated success condition.

### Method
N/A (Illustrative JavaScript code)

### Endpoint
N/A

### Request Example
```javascript
import { makePromiseKit } from '@endo/promise-kit';

function asyncOperation() {
  const { promise, resolve, reject } = makePromiseKit();
  setTimeout(() => {
    const success = true; // Simulating success or failure
    if (success) {
      resolve("Operation successful!");
    } else {
      reject("Operation failed!");
    }
  }, 2000);
  return promise;
}

async function handleAsyncOperation() {
  try {
    const result = await asyncOperation();
    console.log(result); // "Operation successful!"
  } catch (error) {
    console.error(error); // "Operation failed!"
  }
}

handleAsyncOperation();
```

### Response
(Illustrative console output)
```
Operation successful!
```
OR
```
Operation failed!
```
```

--------------------------------

### Install @endo/hex Package

Source: https://github.com/endojs/endo/blob/master/packages/hex/README.md

Install the @endo/hex package using npm.

```sh
npm install @endo/hex
```

--------------------------------

### Install @endo/eslint-plugin

Source: https://github.com/endojs/endo/blob/master/packages/eslint-plugin/README.md

Install the @endo/eslint-plugin package as a development dependency.

```sh
npm install @endo/eslint-plugin --save-dev
```

--------------------------------

### Multiple Promise Kits Example

Source: https://github.com/endojs/endo/blob/master/packages/promise-kit/README.md

Illustrates how to create and manage multiple independent promise kits simultaneously.

```APIDOC
## Creating Multiple Promise Kits

### Description
This example demonstrates the creation and management of multiple promise kits, showing how each kit can be resolved independently.

### Method
N/A (Illustrative JavaScript code)

### Endpoint
N/A

### Request Example
```javascript
import { makePromiseKit } from '@endo/promise-kit';

const kit1 = makePromiseKit();
const kit2 = makePromiseKit();

kit1.promise.then(value => console.log('Kit 1 resolved with:', value));
kit2.promise.then(value => console.log('Kit 2 resolved with:', value));

kit1.resolve('First success');
kit2.resolve('Second success');
```

### Response
(Illustrative console output)
```
Kit 1 resolved with: First success
Kit 2 resolved with: Second success
```
```

--------------------------------

### Round-Trip Example

Source: https://github.com/endojs/endo/blob/master/packages/lp32/README.md

Demonstrates a full round-trip scenario using `makeLp32Reader` and `makeLp32Writer` with `@endo/stream`'s `makePipe`.

```APIDOC
## Round-Trip Example

### Description
This example demonstrates a complete cycle of writing and reading length-prefixed messages using `makeLp32Writer` and `makeLp32Reader` in conjunction with `@endo/stream`'s `makePipe` for creating an in-memory stream.

### Code
```javascript
import { makePipe } from '@endo/stream';
import { makeLp32Reader, makeLp32Writer } from '@endo/lp32';

const [input, output] = makePipe();
const writer = makeLp32Writer(output);
const reader = makeLp32Reader(input);

const encoder = new TextEncoder();
const decoder = new TextDecoder();

// Producer side: Write messages
await writer.next(encoder.encode('message 1'));
await writer.next(encoder.encode('message 2'));
await writer.return();

// Consumer side: Read messages
for await (const message of reader) {
  console.log(decoder.decode(message));
}
```
```

--------------------------------

### Setup Python Virtual Environment

Source: https://github.com/endojs/endo/blob/master/packages/ocapn/test/python-test-suite/README.md

Activate the Python virtual environment before running the test suite. This ensures dependencies are correctly managed.

```bash
source ./venv/bin/activate
```

--------------------------------

### Install Endo and SES

Source: https://github.com/endojs/endo/blob/master/docs/get-started.md

Set up a new Node.js project with ESM support and install the 'ses' package to begin using Endo's HardenedJS features.

```shell
mkdir my-first-endo
cd my-first-endo
echo '{"type": "module"}' > package.json
npm init --yes
npm install ses
```

--------------------------------

### Install SES

Source: https://github.com/endojs/endo/blob/master/packages/ses/README.md

Install the SES shim using npm. This command is used to add SES to your project's dependencies.

```sh
npm install ses
```

--------------------------------

### Clone Repository and Install Dependencies

Source: https://github.com/endojs/endo/blob/master/packages/bundle-source/CONTRIBUTING.md

Clone the EndoJS repository and install the necessary Node.js dependencies.

```bash
git clone https://github.com/Agoric/@REPO@/
npm install
```

--------------------------------

### Install @endo/base64 Package

Source: https://github.com/endojs/endo/blob/master/packages/base64/README.md

Use npm to install the @endo/base64 package. This command is for Node.js environments.

```sh
npm install @endo/base64
```

--------------------------------

### Install @endo/trampoline

Source: https://github.com/endojs/endo/blob/master/packages/trampoline/README.md

Standard installation command for the @endo/trampoline package using npm.

```sh
npm install @endo/trampoline
```

--------------------------------

### Install Familiar Chat Weblet

Source: https://github.com/endojs/endo/blob/master/packages/cli/demo/README.md

Installs the Familiar Chat weblet, granting it agent powers and setting a listening port. This prepares the application to manage your pet store and mailbox.

```bash
> endo install cat.js --listen 8920 --powers AGENT --name familiar-chat
```

--------------------------------

### Round-Trip Message Stream Example

Source: https://github.com/endojs/endo/blob/master/packages/lp32/README.md

Demonstrates a full cycle of writing and reading length-prefixed messages using `makeLp32Writer` and `makeLp32Reader` in conjunction with `makePipe` from `@endo/stream`. This example shows how to produce messages and then consume them from the same stream.

```javascript
import { makePipe } from '@endo/stream';
import { makeLp32Reader, makeLp32Writer } from '@endo/lp32';

const [input, output] = makePipe();
const writer = makeLp32Writer(output);
const reader = makeLp32Reader(input);

const encoder = new TextEncoder();
const decoder = new TextDecoder();

// Producer
await writer.next(encoder.encode('message 1'));
await writer.next(encoder.encode('message 2'));
await writer.return();

// Consumer
for await (const message of reader) {
  console.log(decoder.decode(message));
}
```

--------------------------------

### Usage Example for @endo/bytes

Source: https://github.com/endojs/endo/blob/master/packages/bytes/README.md

Demonstrates common usage patterns including text conversion, byte concatenation, comparison, and handling immutable byte buffers.

```js
import { bytesFromText } from '@endo/bytes/from-string.js';
import { bytesToText } from '@endo/bytes/to-string.js';
import { concatBytes } from '@endo/bytes/concat.js';
import { bytesEqual } from '@endo/bytes/equals.js';
import { bytesToImmutable } from '@endo/bytes/to-immutable.js';
import { bytesFromImmutable } from '@endo/bytes/from-immutable.js';

const a = bytesFromText('Hello, ');
const b = bytesFromText('world!');
const greeting = concatBytes([a, b]);
bytesToText(greeting); // 'Hello, world!'

bytesEqual(bytesFromText('abc'), bytesFromText('abc')); // true

// Wrap a Uint8Array in a passable, immutable ArrayBuffer.
const passable = bytesToImmutable(greeting);
// Recover a working Uint8Array from an immutable buffer received over a vat boundary.
bytesToText(bytesFromImmutable(passable)); // 'Hello, world!'
```

--------------------------------

### Markdown Style Example

Source: https://github.com/endojs/endo/blob/master/CONTRIBUTING.md

Example demonstrating the recommended Markdown style with lines wrapped at 80 to 100 columns and each sentence starting on a new line.

```markdown
The Endo stack provides a layered solution through four packages.
Each package has a specific role in enabling safe message passing.
Together, they form the foundation of distributed computing.
```

--------------------------------

### makeExo: Single Instance Greeter

Source: https://github.com/endojs/endo/blob/master/packages/exo/README.md

Demonstrates creating a single, stateless exo instance using makeExo. This pattern is suitable for utility objects or simple services without instance-specific state.

```javascript
import { makeExo } from '@endo/exo';
import { M } from '@endo/patterns';

const GreeterI = M.interface('Greeter', {
  greet: M.call(M.string()).returns(M.string())
});

const greeter = makeExo('Greeter', GreeterI, {
  greet(name) {
    return `Hello, ${name}!`;
  }
});

greeter.greet('World');  // 'Hello, World!'
```

--------------------------------

### Quick Start: Data Validation with @endo/patterns

Source: https://github.com/endojs/endo/blob/master/packages/patterns/README.md

Use `mustMatch` to validate data against a pattern. This example demonstrates matching a record with required and optional properties, throwing an error if the data does not conform.

```javascript
import { M, mustMatch } from '@endo/patterns';

const specimen = harden({ foo: 3, bar: 4 });

const pattern = M.splitRecord(
  { foo: M.number() },                        // required properties
  { bar: M.string(), baz: M.number() }       // optional properties
);

mustMatch(specimen, pattern);
// throws: 'bar?: number 4 - Must be a string'
```

--------------------------------

### Bundle Source from Command Line

Source: https://github.com/endojs/endo/blob/master/packages/bundle-source/README.md

Use the `bundle-source` tool to create a source bundle from an entry point script. The `--cache-json` option stores the bundle in a cache.

```console
> yarn bundle-source --cache-json bundles program.js program
```

--------------------------------

### Install @endo/bytes

Source: https://github.com/endojs/endo/blob/master/packages/bytes/README.md

Install the @endo/bytes package using npm.

```sh
npm install @endo/bytes
```

--------------------------------

### Build and Publish Release

Source: https://github.com/endojs/endo/blob/master/packages/bundle-source/CONTRIBUTING.md

Build the project for release and publish the package to the registry.

```bash
npm run build
npm publish
```

--------------------------------

### Create and Use a Weak Cache

Source: https://github.com/endojs/endo/blob/master/packages/cache-map/README.md

Demonstrates creating a cache with a size limit and using its WeakMap-compatible methods. Keys are held weakly, so they may be garbage collected. Assertions verify cache behavior including eviction.

```javascript
import { makeCacheMapKit } from '@endo/cache-map';

const { cache: weakCache, getMetrics } = makeCacheMapKit(2);
const entries = [
  { key: Symbol('key 1'), value: Symbol('value 1') },
  { key: Symbol('key 2'), value: Symbol('value 2') },
  { key: Symbol('key 3'), value: Symbol('value 3') },
];
for (const { key, value } of entries) weakCache.set(key, value);

assert(!weakCache.has(entries[0].key));
assert(weakCache.has(entries[1].key));
assert(weakCache.get(entries[2].key) === entries[2].value);

weakCache.delete(entries[2].key);
weakCache.set(entries[1].key, entries[0]);

assert(!weakCache.has(entries[0].key));
assert(!weakCache.has(entries[2].key));
assert(weakCache.get(entries[1].key) === entries[0]);

assert.throws(() => weakCache.set('unweakable key', {}));

```

--------------------------------

### Create Guest and Make Doubler

Source: https://github.com/endojs/endo/blob/master/packages/cli/demo/README.md

CLI commands to create a guest profile for the doubler and then instantiate the doubler agent using its JavaScript file and powers.

```bash
> endo mkguest doubler-handle doubler-agent
> endo make doubler.js --name doubler --powers doubler-agent
```

--------------------------------

### Run Endo Client Against Guile-hosted Sturdyref

Source: https://github.com/endojs/endo/blob/master/packages/goblin-chat/test/guile-interop/README.md

Execute the Endo client to connect to a Guile-hosted chatroom sturdyref. Ensure the sturdyref URI is provided as an argument.

```bash
node ./packages/goblin-chat/test/guile-interop/index.js "ocapn://.../s/..."
```

--------------------------------

### Disable Yarn Install Scripts

Source: https://github.com/endojs/endo/wiki/Mitigating-Postinstall-Attacks-like-the-Shai‐Hulud-Worm

Configure Yarn to disable install scripts by adding `{"enableScripts": false}` to your project's `.yarnrc.yml` file. This prevents arbitrary code execution during installation.

```yaml
enableScripts: false
```

--------------------------------

### Initialize Compartment with ModuleSource

Source: https://github.com/endojs/endo/blob/master/packages/module-source/README.md

Demonstrates setting up a Compartment with custom resolve and import hooks that utilize ModuleSource. Ensure 'ses' and '@endo/module-source' are imported.

```javascript
import 'ses';
import { ModuleSource } from '@endo/module-source';

const c1 = new Compartment({}, {}, {
  name: "first compartment",
  resolveHook: (moduleSpecifier, moduleReferrer) => {
    return resolve(moduleSpecifier, moduleReferrer);
  },
  importHook: async moduleSpecifier => {
    const moduleLocation = locate(moduleSpecifier);
    const moduleText = await retrieve(moduleLocation);
    return new ModuleSource(moduleText, moduleLocation);
  },
});
```

--------------------------------

### Installing @endo/random

Source: https://github.com/endojs/endo/blob/master/packages/random/README.md

Install the @endo/random package using npm. This command is used to add the library to your project's dependencies.

```sh
npm install @endo/random
```

--------------------------------

### Run Endo OCapN Test Server

Source: https://github.com/endojs/endo/blob/master/packages/ocapn/test/python-test-suite/README.md

Start the Node.js server to act as the host for the OCapN test suite. This is the first step in setting up the test environment.

```bash
node ./packages/ocapn/test/python-test-suite/index.js
```

--------------------------------

### Direct Use of Installed harden Property

Source: https://github.com/endojs/endo/blob/master/docs/spackle.md

This snippet demonstrates directly accessing and using the harden function installed on Object using a registered symbol.

```javascript
Object[Symbol.for('harden')](object);
```

--------------------------------

### Initialize CapTP Connection and Bootstrap

Source: https://github.com/endojs/endo/blob/master/packages/captp/README.md

Sets up a CapTP connection, defines a message dispatcher, and initiates the bootstrap process. Ensure 'myconn' is a pre-established connection object and 'myBootstrap' is the remote's bootstrap object. Messages are exchanged as JSON-able objects.

```javascript
import { E, makeCapTP } from '@endo/captp';

// Create a message dispatcher and bootstrap.
// Messages on myconn are exchanged with JSON-able objects.
const { dispatch, getBootstrap, abort } = makeCapTP('myid', myconn.send, myBootstrap);
myconn.onReceive = obj => dispatch(obj);

// Get the remote's bootstrap object and call a remote method.
E(getBootstrap()).method(args).then(res => console.log('got res', res));

// Tear down the CapTP connection if it fails (e.g. connection is closed).
abort(Error('Connection aborted by user.'));
```

--------------------------------

### Example of a Tagged Object

Source: https://github.com/endojs/endo/blob/master/docs/message-passing.md

Illustrates the creation of a 'tagged' object, used as an extension point for domain-specific types. This example shows how to create a tagged 'copySet'.

```javascript
makeTagged('copySet', [...])
```

--------------------------------

### Basic Promise Kit Usage

Source: https://github.com/endojs/endo/blob/master/packages/promise-kit/README.md

Demonstrates how to use `makePromiseKit` to create a promise that is resolved or rejected after a delay. Ensure the `success` variable is set appropriately to simulate different outcomes.

```javascript
import { makePromiseKit } from '@endo/promise-kit';

function asyncOperation() {

  const { promise, resolve, reject } = makePromiseKit();
  setTimeout(() => {
    const success = true; // Simulating success or failure
    if (success) {
      resolve("Operation successful!");
    } else {
      reject("Operation failed!");
    }
  }, 2000); 

  return promise;
}

async function handleAsyncOperation() {
  try {
    const result = await asyncOperation();
    console.log(result); // "Operation successful!"
  } catch (error) {
    console.error(error); // "Operation failed!"
  }
}

handleAsyncOperation();

```

--------------------------------

### Example Module with Diverse Imports and Exports

Source: https://github.com/endojs/endo/blob/master/packages/module-source/DESIGN.md

Illustrates a JavaScript module showcasing various import and export syntaxes, including default, namespace, named, aliased, re-exports, and default exports.

```javascript
import foo from 'import-default-export-from-me.js';
import * as bar from 'import-all-from-me.js';
import { fizz, buzz } from 'import-named-exports-from-me.js';
import { color as colour } from 'import-named-export-and-rename.js';

export let quuux = null;

export { qux } from 'import-and-reexport-name-from-me.js';
export * from 'import-and-export-all.js';
export default 42;
export const quux = 'Hello, World!';

const aleph = 0;
export { aleph as alpha };
export { grey as gray } from './reexport-name-and-rename.js';

// Late binding of an exported variable.
quuux = 'Hello, World!';
```

--------------------------------

### Example of an Error Object

Source: https://github.com/endojs/endo/blob/master/docs/message-passing.md

Illustrates how to create a hardened 'error' object, which can be passed between compartments.

```javascript
harden(Error('failed'))
```

--------------------------------

### Importing and Using makeScript

Source: https://github.com/endojs/endo/blob/master/packages/compartment-mapper/README.md

Demonstrates how to import the makeScript function and use it to generate a JavaScript bundle. Requires fs and url modules for node environments.

```javascript
import url from "node:url";
import fs from "node:fs";
import { makeScript } from "@endo/compartment-mapper/script.js";
import { makeReadPowers } from "@endo/compartment-mapper/node-powers.js";
const readPowers = makeReadPowers({ fs, url });
const options = {}; // if any
const script = await makeScript(readPowers, moduleLocation, options);
```

--------------------------------

### Install @endo/ses-ava as a Dev Dependency

Source: https://github.com/endojs/endo/blob/master/packages/ses-ava/README.md

Add @endo/ses-ava to your package.json's devDependencies to include it in your project.

```json
{
  "devDependencies": {
    // ...
    "@endo/ses-ava": "...", // for the current version of @endo/ses-ava
    // ...
  },
}
```

--------------------------------

### Create Mint and Purse with defineExoClassKit

Source: https://github.com/endojs/endo/blob/master/docs/message-passing.md

Defines a 'Mint' kit with 'mint' and 'purse' facets. The purse facet is stateful, starting with a balance of 0. The makePurse method on the mint facet returns the purse facet.

```javascript
// Step 2: Define the Mint/Purse Kit

const makeMintKit = defineExoClassKit(
  'Mint',
  { mint: MintI, purse: PurseI },

  // init: each purse starts with 0 balance
  () => ({ balance: 0 }),

  {
    mint: {
      makePurse() {
        // Return the purse facet, not the mint facet
        // This ensures the holder of a purse can't mint
        return this.facets.purse;
      }
    },

    purse: {
      getBalance() {
        return this.state.balance;
      },

      async deposit(amount, payment) {
        // amount is validated as non-negative number by guard
        // payment is validated as remotable by guard

        // Get payment's balance (eventual send)
        const paymentBalance = await E(payment).getBalance();

        // Verify amount matches
        if (paymentBalance !== amount) {
          throw Error('Payment balance mismatch');
        }

        // Add to our balance
        this.state.balance += amount;
      },

      withdraw(amount) {
        // amount is validated as non-negative by guard

        if (amount > this.state.balance) {
          throw Error('Insufficient balance');
        }

        // Deduct from balance
        this.state.balance -= amount;

        // Create a new payment
        return makePayment(amount);
      }
    }
  }
);

```

--------------------------------

### Promise Pipelining Example

Source: https://github.com/endojs/endo/blob/master/packages/eventual-send/README.md

Demonstrates promise pipelining by sending messages to promises before they resolve, significantly reducing latency in distributed systems by queuing messages and delivering them in order upon resolution.

```javascript
import { E } from '@endo/eventual-send';

// All of these send immediately - no waiting!
const mintP = E(bootstrap).getMint();
const purseP = E(mintP).makePurse();
const paymentP = E(purseP).withdraw(100);
await E(receiverPurse).deposit(100, paymentP);

// Only wait at the end for the final result
```

--------------------------------

### Configure Compartment with importNowHook

Source: https://github.com/endojs/endo/blob/master/packages/ses/README.md

Demonstrates setting up a Compartment with both asynchronous `importHook` and synchronous `importNowHook`. The `importNowHook` is used for platform-specific synchronous reads.

```javascript
import 'ses';
import { ModuleSource } from '@endo/module-source';

const compartment = new Compartment({
  name: "first compartment",
  modules: {
    c: {
      source: new ModuleSource(''),
    },
  },
  resolveHook: (moduleSpecifier, moduleReferrer) => {
    return resolve(moduleSpecifier, moduleReferrer);
  },
  importHook: async moduleSpecifier => {
    const moduleLocation = locate(moduleSpecifier);
    const moduleText = await retrieve(moduleLocation);
    return {
      source: new ModuleSource(moduleText, moduleLocation),
    };
  },
  importNowHook: moduleSpecifier => {
    const moduleLocation = locate(moduleSpecifier);
    // Platform-specific synchronous read API can be used
    const moduleText = fs.readFileSync(moduleLocation);
    return {
      source: new ModuleSource(moduleText, moduleLocation),
    };
  },
  __options__: true, // temporary migration affordance
});
//...                   | importHook | importNowHook
await compartment.import('a'); //| called     | not called
compartment.importNow('b');    //| not called | called
compartment.importNow('a');    //| not called | not called
compartment.importNow('c');    //| not called | not called

```

--------------------------------

### Prepare SES-AVA Test Environment

Source: https://github.com/endojs/endo/blob/master/packages/ses-ava/README.md

Replace standard AVA imports with this to initialize the SES-shim with options suitable for debugging tests. Ensure '@endo/ses-ava' is in your devDependencies.

```javascript
import test from '@endo/ses-ava/prepare-endo.js';
```

--------------------------------

### Insecure Counter Implementation

Source: https://github.com/endojs/endo/blob/master/packages/ses/docs/secure-coding-guide.md

This counter example is insecure because the returned object is not hardened, allowing external modification of its methods.

```javascript
// insecure
function makeCounter() {
  let count = 0;
  function increment() {
    count += 1;
  }
  function decrement() {
    count -= 1;
  }
  function read() {
    return count;
  }
  const updown = { increment, decrement };
  return { updown, read };
}
```

--------------------------------

### Example of HTML-like comment in code

Source: https://github.com/endojs/endo/blob/master/packages/ses/error-codes/SES_HTML_COMMENT_REJECTED.md

This code demonstrates a scenario where an HTML-like comment might be present, which SES will reject.

```javascript
a <!-- b
```

--------------------------------

### Example of a Copy Record

Source: https://github.com/endojs/endo/blob/master/docs/message-passing.md

Demonstrates the creation of a 'copyRecord', a frozen plain object. This is another pass-by-copy data structure.

```javascript
harden({ x: 10 })
```

--------------------------------

### Example of a Copy Array

Source: https://github.com/endojs/endo/blob/master/docs/message-passing.md

Shows how to create a 'copyArray', which is a frozen array of passable values. This is a pass-by-copy data structure.

```javascript
harden([1, 2, 3])
```

--------------------------------

### Guessing Zero Code with Generator

Source: https://github.com/endojs/endo/blob/master/packages/ses/demos/challenge/README.md

A simple generator function that immediately guesses '0000000000'. This is a basic example of an attacker program.

```javascript
function* guessZeros() {
  guess('0000000000');
}
```

--------------------------------

### Stateless Utility with makeExo

Source: https://github.com/endojs/endo/blob/master/docs/message-passing.md

Use `makeExo` for single instances with state managed in closure variables, suitable for simple, stateless utilities.

```javascript
const validator = makeExo('Validator', ValidatorI, {
  validate(data) {
    return checkRules(data);
  }
});
```

--------------------------------

### String Encoding

Source: https://github.com/endojs/endo/blob/master/packages/marshal/docs/smallcaps-cheatsheet.md

Represents JavaScript strings in Smallcaps encoding. Strings starting with special characters like '!' are encoded differently.

```javascript
'#foo'
```

```javascript
'foo'
```

--------------------------------

### Using Shims Between Lockdown Phases

Source: https://github.com/endojs/endo/blob/master/docs/guide.md

This example shows how to integrate custom shims or vetted modules between the repairIntrinsics and hardenIntrinsics phases. Ensure that any shims used preserve the integrity invariants of your application.

```javascript
import './non-ses-code-before-lockdown.js';
import './ses-repair-intrinsics.js'; // calls repairIntrinsics. 
import './vetted-shim.js';
import './ses-harden-intrinsics.js'; // calls hardenIntrinsics. 
import './ses-code-after-lockdown.js';
```