proxy-freeze

A simple way to freeze JavaScript objects and know of attempted modifications.

Why?

Why not just use Object.freeze and Object.isFrozen?

If you use Object.freeze and later set a property on that object, it silently fails unless in strict mode. Also, using this technique gives you the ability to listen for warnings on the warning event.

Install

npm install --save proxy-freeze

Usage

proxyFreeze(target, options)

• target: can be either an object or constructor function
• options
  • addProxyIdentifier: boolean, adds a symbol getter that detects Proxies created via this method. Defaults to false.
  • preventRefreeze: boolean, uses symbol added via addProxyIdentifier to identify frozen Proxies and doesn't re-freeze them. Defaults to false.

const obj = {
  name: 'jp',
}

const obj2 = proxyFreeze(obj)
obj2.name = 'bob'

process.once('warning', (warning) => {
  console.warn(warning.name) // => ProxyFreezeWarning
  console.warn(warning.message) // => Trying to set value of property (name) of frozen object.
  console.warn(warning.stack)
})

License

MIT