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/** | |
* Utility function that works like `Object.apply`, but copies getters and setters properly as well. Additionally gives | |
* the option to exclude properties by name. | |
*/ | |
const copyProps = (dest, src, exclude = []) => { | |
const props = Object.getOwnPropertyDescriptors(src); | |
for (let prop of exclude) | |
delete props[prop]; | |
Object.defineProperties(dest, props); | |
}; | |
/** | |
* Returns the full chain of prototypes up until Object.prototype given a starting object. The order of prototypes will | |
* be closest to farthest in the chain. | |
*/ | |
const protoChain = (obj, currentChain = [obj]) => { | |
const proto = Object.getPrototypeOf(obj); | |
if (proto === null) | |
return currentChain; | |
return protoChain(proto, [...currentChain, proto]); | |
}; | |
/** | |
* Identifies the nearest ancestor common to all the given objects in their prototype chains. For most unrelated | |
* objects, this function should return Object.prototype. | |
*/ | |
const nearestCommonProto = (...objs) => { | |
if (objs.length === 0) | |
return undefined; | |
let commonProto = undefined; | |
const protoChains = objs.map(obj => protoChain(obj)); | |
while (protoChains.every(protoChain => protoChain.length > 0)) { | |
const protos = protoChains.map(protoChain => protoChain.pop()); | |
const potentialCommonProto = protos[0]; | |
if (protos.every(proto => proto === potentialCommonProto)) | |
commonProto = potentialCommonProto; | |
else | |
break; | |
} | |
return commonProto; | |
}; | |
/** | |
* Creates a new prototype object that is a mixture of the given prototypes. The mixing is achieved by first | |
* identifying the nearest common ancestor and using it as the prototype for a new object. Then all properties/methods | |
* downstream of this prototype (ONLY downstream) are copied into the new object. | |
* | |
* The resulting prototype is more performant than softMixProtos(...), as well as ES5 compatible. However, it's not as | |
* flexible as updates to the source prototypes aren't captured by the mixed result. See softMixProtos for why you may | |
* want to use that instead. | |
*/ | |
const hardMixProtos = (ingredients, constructor, exclude = []) => { | |
var _a; | |
const base = (_a = nearestCommonProto(...ingredients)) !== null && _a !== void 0 ? _a : Object.prototype; | |
const mixedProto = Object.create(base); | |
// Keeps track of prototypes we've already visited to avoid copying the same properties multiple times. We init the | |
// list with the proto chain below the nearest common ancestor because we don't want any of those methods mixed in | |
// when they will already be accessible via prototype access. | |
const visitedProtos = protoChain(base); | |
for (let prototype of ingredients) { | |
let protos = protoChain(prototype); | |
// Apply the prototype chain in reverse order so that old methods don't override newer ones. | |
for (let i = protos.length - 1; i >= 0; i--) { | |
let newProto = protos[i]; | |
if (visitedProtos.indexOf(newProto) === -1) { | |
copyProps(mixedProto, newProto, ['constructor', ...exclude]); | |
visitedProtos.push(newProto); | |
} | |
} | |
} | |
mixedProto.constructor = constructor; | |
return mixedProto; | |
}; | |
const unique = (arr) => arr.filter((e, i) => arr.indexOf(e) == i); | |
/** | |
* Finds the ingredient with the given prop, searching in reverse order and breadth-first if searching ingredient | |
* prototypes is required. | |
*/ | |
const getIngredientWithProp = (prop, ingredients) => { | |
const protoChains = ingredients.map(ingredient => protoChain(ingredient)); | |
// since we search breadth-first, we need to keep track of our depth in the prototype chains | |
let protoDepth = 0; | |
// not all prototype chains are the same depth, so this remains true as long as at least one of the ingredients' | |
// prototype chains has an object at this depth | |
let protosAreLeftToSearch = true; | |
while (protosAreLeftToSearch) { | |
// with the start of each horizontal slice, we assume this is the one that's deeper than any of the proto chains | |
protosAreLeftToSearch = false; | |
// scan through the ingredients right to left | |
for (let i = ingredients.length - 1; i >= 0; i--) { | |
const searchTarget = protoChains[i][protoDepth]; | |
if (searchTarget !== undefined && searchTarget !== null) { | |
// if we find something, this is proof that this horizontal slice potentially more objects to search | |
protosAreLeftToSearch = true; | |
// eureka, we found it | |
if (Object.getOwnPropertyDescriptor(searchTarget, prop) != undefined) { | |
return protoChains[i][0]; | |
} | |
} | |
} | |
protoDepth++; | |
} | |
return undefined; | |
}; | |
/** | |
* "Mixes" ingredients by wrapping them in a Proxy. The optional prototype argument allows the mixed object to sit | |
* downstream of an existing prototype chain. Note that "properties" cannot be added, deleted, or modified. | |
*/ | |
const proxyMix = (ingredients, prototype = Object.prototype) => new Proxy({}, { | |
getPrototypeOf() { | |
return prototype; | |
}, | |
setPrototypeOf() { | |
throw Error('Cannot set prototype of Proxies created by ts-mixer'); | |
}, | |
getOwnPropertyDescriptor(_, prop) { | |
return Object.getOwnPropertyDescriptor(getIngredientWithProp(prop, ingredients) || {}, prop); | |
}, | |
defineProperty() { | |
throw new Error('Cannot define new properties on Proxies created by ts-mixer'); | |
}, | |
has(_, prop) { | |
return getIngredientWithProp(prop, ingredients) !== undefined || prototype[prop] !== undefined; | |
}, | |
get(_, prop) { | |
return (getIngredientWithProp(prop, ingredients) || prototype)[prop]; | |
}, | |
set(_, prop, val) { | |
const ingredientWithProp = getIngredientWithProp(prop, ingredients); | |
if (ingredientWithProp === undefined) | |
throw new Error('Cannot set new properties on Proxies created by ts-mixer'); | |
ingredientWithProp[prop] = val; | |
return true; | |
}, | |
deleteProperty() { | |
throw new Error('Cannot delete properties on Proxies created by ts-mixer'); | |
}, | |
ownKeys() { | |
return ingredients | |
.map(Object.getOwnPropertyNames) | |
.reduce((prev, curr) => curr.concat(prev.filter(key => curr.indexOf(key) < 0))); | |
}, | |
}); | |
/** | |
* Creates a new proxy-prototype object that is a "soft" mixture of the given prototypes. The mixing is achieved by | |
* proxying all property access to the ingredients. This is not ES5 compatible and less performant. However, any | |
* changes made to the source prototypes will be reflected in the proxy-prototype, which may be desirable. | |
*/ | |
const softMixProtos = (ingredients, constructor) => proxyMix([...ingredients, { constructor }]); | |
const settings = { | |
initFunction: null, | |
staticsStrategy: 'copy', | |
prototypeStrategy: 'copy', | |
decoratorInheritance: 'deep', | |
}; | |
// Keeps track of constituent classes for every mixin class created by ts-mixer. | |
const mixins = new WeakMap(); | |
const getMixinsForClass = (clazz) => mixins.get(clazz); | |
const registerMixins = (mixedClass, constituents) => mixins.set(mixedClass, constituents); | |
const hasMixin = (instance, mixin) => { | |
if (instance instanceof mixin) | |
return true; | |
const constructor = instance.constructor; | |
const visited = new Set(); | |
let frontier = new Set(); | |
frontier.add(constructor); | |
while (frontier.size > 0) { | |
// check if the frontier has the mixin we're looking for. if not, we can say we visited every item in the frontier | |
if (frontier.has(mixin)) | |
return true; | |
frontier.forEach((item) => visited.add(item)); | |
// build a new frontier based on the associated mixin classes and prototype chains of each frontier item | |
const newFrontier = new Set(); | |
frontier.forEach((item) => { | |
var _a; | |
const itemConstituents = (_a = mixins.get(item)) !== null && _a !== void 0 ? _a : protoChain(item.prototype) | |
.map((proto) => proto.constructor) | |
.filter((item) => item !== null); | |
if (itemConstituents) | |
itemConstituents.forEach((constituent) => { | |
if (!visited.has(constituent) && !frontier.has(constituent)) | |
newFrontier.add(constituent); | |
}); | |
}); | |
// we have a new frontier, now search again | |
frontier = newFrontier; | |
} | |
// if we get here, we couldn't find the mixin anywhere in the prototype chain or associated mixin classes | |
return false; | |
}; | |
const mergeObjectsOfDecorators = (o1, o2) => { | |
var _a, _b; | |
const allKeys = unique([...Object.getOwnPropertyNames(o1), ...Object.getOwnPropertyNames(o2)]); | |
const mergedObject = {}; | |
for (let key of allKeys) | |
mergedObject[key] = unique([...((_a = o1 === null || o1 === void 0 ? void 0 : o1[key]) !== null && _a !== void 0 ? _a : []), ...((_b = o2 === null || o2 === void 0 ? void 0 : o2[key]) !== null && _b !== void 0 ? _b : [])]); | |
return mergedObject; | |
}; | |
const mergePropertyAndMethodDecorators = (d1, d2) => { | |
var _a, _b, _c, _d; | |
return ({ | |
property: mergeObjectsOfDecorators((_a = d1 === null || d1 === void 0 ? void 0 : d1.property) !== null && _a !== void 0 ? _a : {}, (_b = d2 === null || d2 === void 0 ? void 0 : d2.property) !== null && _b !== void 0 ? _b : {}), | |
method: mergeObjectsOfDecorators((_c = d1 === null || d1 === void 0 ? void 0 : d1.method) !== null && _c !== void 0 ? _c : {}, (_d = d2 === null || d2 === void 0 ? void 0 : d2.method) !== null && _d !== void 0 ? _d : {}), | |
}); | |
}; | |
const mergeDecorators = (d1, d2) => { | |
var _a, _b, _c, _d, _e, _f; | |
return ({ | |
class: unique([...(_a = d1 === null || d1 === void 0 ? void 0 : d1.class) !== null && _a !== void 0 ? _a : [], ...(_b = d2 === null || d2 === void 0 ? void 0 : d2.class) !== null && _b !== void 0 ? _b : []]), | |
static: mergePropertyAndMethodDecorators((_c = d1 === null || d1 === void 0 ? void 0 : d1.static) !== null && _c !== void 0 ? _c : {}, (_d = d2 === null || d2 === void 0 ? void 0 : d2.static) !== null && _d !== void 0 ? _d : {}), | |
instance: mergePropertyAndMethodDecorators((_e = d1 === null || d1 === void 0 ? void 0 : d1.instance) !== null && _e !== void 0 ? _e : {}, (_f = d2 === null || d2 === void 0 ? void 0 : d2.instance) !== null && _f !== void 0 ? _f : {}), | |
}); | |
}; | |
const decorators = new Map(); | |
const findAllConstituentClasses = (...classes) => { | |
var _a; | |
const allClasses = new Set(); | |
const frontier = new Set([...classes]); | |
while (frontier.size > 0) { | |
for (let clazz of frontier) { | |
const protoChainClasses = protoChain(clazz.prototype).map(proto => proto.constructor); | |
const mixinClasses = (_a = getMixinsForClass(clazz)) !== null && _a !== void 0 ? _a : []; | |
const potentiallyNewClasses = [...protoChainClasses, ...mixinClasses]; | |
const newClasses = potentiallyNewClasses.filter(c => !allClasses.has(c)); | |
for (let newClass of newClasses) | |
frontier.add(newClass); | |
allClasses.add(clazz); | |
frontier.delete(clazz); | |
} | |
} | |
return [...allClasses]; | |
}; | |
const deepDecoratorSearch = (...classes) => { | |
const decoratorsForClassChain = findAllConstituentClasses(...classes) | |
.map(clazz => decorators.get(clazz)) | |
.filter(decorators => !!decorators); | |
if (decoratorsForClassChain.length == 0) | |
return {}; | |
if (decoratorsForClassChain.length == 1) | |
return decoratorsForClassChain[0]; | |
return decoratorsForClassChain.reduce((d1, d2) => mergeDecorators(d1, d2)); | |
}; | |
const directDecoratorSearch = (...classes) => { | |
const classDecorators = classes.map(clazz => getDecoratorsForClass(clazz)); | |
if (classDecorators.length === 0) | |
return {}; | |
if (classDecorators.length === 1) | |
return classDecorators[0]; | |
return classDecorators.reduce((d1, d2) => mergeDecorators(d1, d2)); | |
}; | |
const getDecoratorsForClass = (clazz) => { | |
let decoratorsForClass = decorators.get(clazz); | |
if (!decoratorsForClass) { | |
decoratorsForClass = {}; | |
decorators.set(clazz, decoratorsForClass); | |
} | |
return decoratorsForClass; | |
}; | |
const decorateClass = (decorator) => ((clazz) => { | |
const decoratorsForClass = getDecoratorsForClass(clazz); | |
let classDecorators = decoratorsForClass.class; | |
if (!classDecorators) { | |
classDecorators = []; | |
decoratorsForClass.class = classDecorators; | |
} | |
classDecorators.push(decorator); | |
return decorator(clazz); | |
}); | |
const decorateMember = (decorator) => ((object, key, ...otherArgs) => { | |
var _a, _b, _c; | |
const decoratorTargetType = typeof object === 'function' ? 'static' : 'instance'; | |
const decoratorType = typeof object[key] === 'function' ? 'method' : 'property'; | |
const clazz = decoratorTargetType === 'static' ? object : object.constructor; | |
const decoratorsForClass = getDecoratorsForClass(clazz); | |
const decoratorsForTargetType = (_a = decoratorsForClass === null || decoratorsForClass === void 0 ? void 0 : decoratorsForClass[decoratorTargetType]) !== null && _a !== void 0 ? _a : {}; | |
decoratorsForClass[decoratorTargetType] = decoratorsForTargetType; | |
let decoratorsForType = (_b = decoratorsForTargetType === null || decoratorsForTargetType === void 0 ? void 0 : decoratorsForTargetType[decoratorType]) !== null && _b !== void 0 ? _b : {}; | |
decoratorsForTargetType[decoratorType] = decoratorsForType; | |
let decoratorsForKey = (_c = decoratorsForType === null || decoratorsForType === void 0 ? void 0 : decoratorsForType[key]) !== null && _c !== void 0 ? _c : []; | |
decoratorsForType[key] = decoratorsForKey; | |
// @ts-ignore: array is type `A[] | B[]` and item is type `A | B`, so technically a type error, but it's fine | |
decoratorsForKey.push(decorator); | |
// @ts-ignore | |
return decorator(object, key, ...otherArgs); | |
}); | |
const decorate = (decorator) => ((...args) => { | |
if (args.length === 1) | |
return decorateClass(decorator)(args[0]); | |
return decorateMember(decorator)(...args); | |
}); | |
function Mixin(...constructors) { | |
var _a, _b, _c; | |
const prototypes = constructors.map(constructor => constructor.prototype); | |
// Here we gather up the init functions of the ingredient prototypes, combine them into one init function, and | |
// attach it to the mixed class prototype. The reason we do this is because we want the init functions to mix | |
// similarly to constructors -- not methods, which simply override each other. | |
const initFunctionName = settings.initFunction; | |
if (initFunctionName !== null) { | |
const initFunctions = prototypes | |
.map(proto => proto[initFunctionName]) | |
.filter(func => typeof func === 'function'); | |
const combinedInitFunction = function (...args) { | |
for (let initFunction of initFunctions) | |
initFunction.apply(this, args); | |
}; | |
const extraProto = { [initFunctionName]: combinedInitFunction }; | |
prototypes.push(extraProto); | |
} | |
function MixedClass(...args) { | |
for (const constructor of constructors) | |
// @ts-ignore: potentially abstract class | |
copyProps(this, new constructor(...args)); | |
if (initFunctionName !== null && typeof this[initFunctionName] === 'function') | |
this[initFunctionName].apply(this, args); | |
} | |
MixedClass.prototype = settings.prototypeStrategy === 'copy' | |
? hardMixProtos(prototypes, MixedClass) | |
: softMixProtos(prototypes, MixedClass); | |
Object.setPrototypeOf(MixedClass, settings.staticsStrategy === 'copy' | |
? hardMixProtos(constructors, null, ['prototype']) | |
: proxyMix(constructors, Function.prototype)); | |
let DecoratedMixedClass = MixedClass; | |
if (settings.decoratorInheritance !== 'none') { | |
const classDecorators = settings.decoratorInheritance === 'deep' | |
? deepDecoratorSearch(...constructors) | |
: directDecoratorSearch(...constructors); | |
for (let decorator of (_a = classDecorators === null || classDecorators === void 0 ? void 0 : classDecorators.class) !== null && _a !== void 0 ? _a : []) { | |
const result = decorator(DecoratedMixedClass); | |
if (result) { | |
DecoratedMixedClass = result; | |
} | |
} | |
applyPropAndMethodDecorators((_b = classDecorators === null || classDecorators === void 0 ? void 0 : classDecorators.static) !== null && _b !== void 0 ? _b : {}, DecoratedMixedClass); | |
applyPropAndMethodDecorators((_c = classDecorators === null || classDecorators === void 0 ? void 0 : classDecorators.instance) !== null && _c !== void 0 ? _c : {}, DecoratedMixedClass.prototype); | |
} | |
registerMixins(DecoratedMixedClass, constructors); | |
return DecoratedMixedClass; | |
} | |
const applyPropAndMethodDecorators = (propAndMethodDecorators, target) => { | |
const propDecorators = propAndMethodDecorators.property; | |
const methodDecorators = propAndMethodDecorators.method; | |
if (propDecorators) | |
for (let key in propDecorators) | |
for (let decorator of propDecorators[key]) | |
decorator(target, key); | |
if (methodDecorators) | |
for (let key in methodDecorators) | |
for (let decorator of methodDecorators[key]) | |
decorator(target, key, Object.getOwnPropertyDescriptor(target, key)); | |
}; | |
/** | |
* A decorator version of the `Mixin` function. You'll want to use this instead of `Mixin` for mixing generic classes. | |
*/ | |
const mix = (...ingredients) => decoratedClass => { | |
// @ts-ignore | |
const mixedClass = Mixin(...ingredients.concat([decoratedClass])); | |
Object.defineProperty(mixedClass, 'name', { | |
value: decoratedClass.name, | |
writable: false, | |
}); | |
return mixedClass; | |
}; | |
export { Mixin, decorate, hasMixin, mix, settings }; | |