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const unbound = Symbol('unbound') | |
const bindMethod = (obj, fn) => { | |
const value = fn[unbound] || fn | |
return Object.assign(value.bind(obj), { [unbound]: value }) | |
} | |
const bindObjMethods = obj => { | |
const proto = Object.getPrototypeOf(obj) | |
for (const name of Object.getOwnPropertyNames(proto)) { | |
if (name === 'constructor') | |
continue | |
const descriptor = Object.getOwnPropertyDescriptor(proto, name) | |
if (('value' in descriptor) && typeof descriptor.value === 'function') { | |
descriptor.value = bindMethod(obj, descriptor.value) | |
Object.defineProperty(obj, name, descriptor) | |
} | |
if (typeof descriptor.get === 'function' || typeof descriptor.set === 'function') { | |
const { get, set } = descriptor | |
if (typeof get === 'function') { | |
descriptor.get = () => { | |
const value = get.call(obj) | |
return typeof value !== 'function' ? value | |
: bindMethod(obj, value) | |
} | |
} | |
if (typeof set === 'function') { | |
descriptor.set = value => { | |
value = typeof value !== 'function' ? value | |
: bindMethod(obj, value) | |
set.call(obj, value) | |
} | |
} | |
} | |
Object.defineProperty(obj, name, descriptor) | |
} | |
} | |
class A { | |
method () { | |
return this | |
} | |
} | |
class B { | |
_method () { | |
return this | |
} | |
get method () { | |
return this._method | |
} | |
set method (value) { | |
this._method = value | |
} | |
} | |
const a = Object.assign(new A(), { a: 1 }) | |
bindObjMethods(a) | |
const { method: aMethod } = a | |
const b = Object.assign(new B(), { b: 2 }) | |
bindObjMethods(b) | |
const { method: bMethod } = b | |
console.log('a.method()', a.method()) | |
console.log('aMethod()', aMethod()) | |
console.log('b.method()', b.method()) | |
console.log('bMethod()', bMethod()) | |
const c = { c: 3 } | |
b.method = function () { return [this, c] } | |
const { method: changedBMethod } = b | |
console.log('changed b.method()', b.method()) | |
console.log('changedBMethod()', changedBMethod()) | |
const bChild = Object.assign(Object.create(b), {bChild: 4}) | |
bindObjMethods(bChild) | |
const { method: bChildMethod } = bChild | |
console.log('bChild.method()', bChild.method()) | |
console.log('bChildMethod()', bChildMethod()) | |
/* | |
a.method() A { a: 1 } | |
aMethod() A { a: 1 } | |
b.method() B { b: 2 } | |
bMethod() B { b: 2 } | |
changed b.method() [ B { b: 2 }, { c: 3 } ] | |
changedBMethod() [ B { b: 2 }, { c: 3 } ] | |
bChild.method() [ B { bChild: 4, b: 2 }, { c: 3 } ] | |
bChildMethod() [ B { bChild: 4, b: 2 }, { c: 3 } ] | |
*/ |
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