@aboutweb/proxyscope
v3.0.1
Published
Bootstrap for combining object be reference with ES proxy, and reusing them on other proxy-factories.
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ProxyScope
Bootstrap for combining object be reference with ES proxy, and reusing them on other proxy-factories. Which will also reflect changes made to the original objects. Proxies can also be useful when using immutables or mixins.
Caution this method uses Proxies and therefor will only work in modern enviroments. Please view CanIUse for more information.
Install
npm i @aboutweb/proxyscope
Caution this method uses Proxies and therefor will only work in modern enviroments. Please view CanIUse for more information.
ProxyFactory(`...(traps || factory))
traps
chain of traps merged for the new Proxy
factory
a previous created factory
returns a factory
function with a traps
property
factory(Object target | Array<Object target>
, ...traps
)
target
an object or array of object to use as stack for lookups
traps
to combine while creating a new proxy
Example
import { default as proxyFactory } from "@aboutweb/proxyscope";
import otherFactory from "./otherfactory.js";
const traps = {
has(target, property, receiver) {
return this.findHost(property);
},
/*helper method*/
findHost(property, root) {
let host = this.stack.find(function(level) {
return property in level;
});
if(host) {
return host;
}
if(root === true) {
return this.stack[0];
}
}
}
const factory = proxyFactory(traps, otherfactory);
export {
factory as default,
traps
}
ProxyScope.read
Uses the target.stack
to look up properties.
Example
import { read as proxyRead } from "@aboutweb/proxyscope";
let defaultConfig = {
fu : "bar"
}
function someFn(config) {
let proxy = proxyRead(config, defaultConfig);
expect(proxy.fu).to.equal("bar");
expect(proxy.bar).to.equal("baz");
}
someFn({
bar : "baz"
});
ProxyScope.write
same as proxyRead but will also forward writes if they are defined somewhere in the level chain.
Example
const l1 = {
some : "value"
}
const l2 = {
fu : "bar"
}
let proxy = proxyWrite(l1, l2);
proxy.fu = "hallo";
expect(l2.fu).to.equal("hallo");
ProxyScope.readDeep
read even nested objects, extends proxy-read by returning a new proxy for every property that has multiple possible getters
Use wisely, because this will create a proxy for every property lookup that has more then one possible value. Therefor it is recommended to cache lookups when possible.
Example
import { readDeep as proxyReadDeep } from "@aboutweb/proxyscope";
const l1 = {
nested : {
some : "value",
}
}
const l2 = {
nested : {
fu : "bar"
}
}
const l3 = {
other : true
}
let proxy = proxyReadDeep(l1, l2, l3);
//before caching or update cache afterwords
l3.nested = {
deep : true
}
//cache the returned proxy
let nested = proxy.nested;
expect(nested.some).to.equal("value");
expect(nested.fu).to.equal("bar");
expect(nested.deep).to.equal(true);
ProxyScope.writeDeep
same as proxyReadDeep, but will also write to nested objects
Example
import { writeDeep as proxyWriteDeep } from "@aboutweb/proxyscope";
const l1 = {
nested : {
some : "value",
}
}
const l2 = {
nested : {
fu : "bar"
}
}
let proxy = proxyReadDeep(l1, l2);
//also use cache where possible
let nested = proxy.nested;
nested.some = "other";
nested.fu = "baz";
expect(l1.nested.some).to.equal("other");
expect(l2.nested.fu).to.equal("baz");
Licence
ISC