samvvThis is a library which enables users to "trap" deeply nested objects into
proxies. The API is identical to the proxy API, except that traps get
an additional this context with a method for nesting the current proxied
object into a deeper one.
✨ Now updated with support for TypeScript! See the change log for more information.
🚀 All external dependencies have been stripped, making this library self-contained!
Examples
A simple example for DSL query building:
const DeepProxy = require('proxy-deep');
const db = new DeepProxy({}, {
get(target, path, receiver) {
return this.nest(function () {})
},
apply(target, thisArg, argList) {
return this.path;
}
})
console.log(db.select.from.where()) // outputs ['select', 'from', 'where']Another example using Node's process object:
const DeepProxy = require('proxy-deep')
const { EventEmitter } = require('events')
const emitter = new EventEmitter()
const pp = DeepProxy(process, {
get(target, key, receiver) {
const val = Reflect.get(target, key, receiver);
if (typeof val === 'object' && val !== null) {
return this.nest({})
} else {
emitter.emit('access', this.path)
return val
}
}
})
emitter.on('access', path => {
console.log(`${path} was accessed.`)
})
pp.argv[0] // trapped!API
import DeepProxy from "proxy-deep"import { DeepProxy, TrapThisArgument, DeepProxyHandler } from "proxy-deep"TrapThisArgument<T>
A TypeScript type that holds all information about the this argument inside a
proxy trap.
To speed things up, the same this-argument is shared between calls to
different traps. You should not make use of this implementation detail, and
instead pass any information you wish to share in a custom object inside
options.userData.
new DeepProxy(target, handlers, [options])
Identical to new Proxy(target, handlers), except that the callbacks provided
in the traps object will be called wiith a this-context that has some
additional properties. For a full reference on what arguments are provided to
the handlers, please consult the a
MDN web docs.
options is an object that can contain the following entries:
- path either a string denoting the full path to the object or an array of property keys
- userData an object of which the enumerable properties will be copied to
the
this-argument of a proxy trap handler
this.rootTarget
A reference to the object with wich the deep proxy was created.
this.path
Holds the full property path to the given object.
this.nest([nestedTarget])
Returns a new proxy that will trap methods as described in this API.
nestedTarget is an optional object with which the proxy will be initialized.
If it is not specified, the target that was passed to new DeepProxy() will be
used.
handler.getPrototypeOf()
A trap for Object.getPrototypeOf.
handler.setPrototypeOf()
A trap for Object.setPrototypeOf.
handler.isExtensible()
A trap for Object.isExtensible.
handler.preventExtensions()
A trap for Object.preventExtensions.
handler.getOwnPropertyDescriptor()
A trap for Object.getOwnPropertyDescriptor.
handler.defineProperty()
A trap for Object.defineProperty.
handler.has()
A trap for the in operator.
handler.get()
A trap for getting property values.
handler.set()
A trap for setting property values.
handler.deleteProperty()
A trap for the delete operator.
handler.ownKeys()
A trap for Object.getOwnPropertyNames and Object.getOwnPropertySymbols.
handler.apply()
A trap for a function call.
handler.construct()
A trap for the new operator.
FAQ
I get an error foo is not a function!
You must pass a fuction as the object to be proxied if you want traps.apply to work, like so:
const proxy = new DeepProxy(function () {}, {
apply() {
return 42;
}
});License
The MIT License