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Adding much more granular Set/Map acceptance tests and replacements, …
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…to preserve as much of the original implementation as possible.

Relates to paulmillr#326.
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@ljharb
ljharb committed Apr 8, 2015
1 parent a26b4fd commit a629e53
Showing 1 changed file with 169 additions and 13 deletions.
182 changes: 169 additions & 13 deletions es6-shim.js
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Original file line number Diff line number Diff line change
Expand Up @@ -39,10 +39,13 @@
var supportsSubclassing = function (C, f) {
/* jshint proto:true */
try {
var Sub = function () { C.apply(this, arguments); };
if (!Sub.__proto__) { return false; /* skip test on IE < 11 */ }
Object.setPrototypeOf(Sub, C);
Sub.prototype = Object.create(C.prototype, {
if (!Object.setPrototypeOf) { return false; /* skip test on IE < 11 */ }
var Sub = function Subclass(arg) {
var o = new C(arg);
Object.setPrototypeOf(o, Subclass.prototype);
return o;
};
Sub.prototype = create(C.prototype, {
constructor: { value: C }
});
return f(Sub);
Expand Down Expand Up @@ -2412,6 +2415,159 @@
defineProperties(globals, collectionShims);

if (globals.Map || globals.Set) {
var mapAcceptsArguments = (function () {
// Safari 8, for example, doesn't accept an iterable.
try {
return new Map([[1, 2]]).get(1) === 2;
} catch (e) {
return false;
}
}());
if (!mapAcceptsArguments) {
var OrigMapNoArgs = globals.Map;
globals.Map = function Map(iterable) {
if (!(this instanceof Map)) {
throw new TypeError('Constructor Map requires "new"');
}
var m = new OrigMapNoArgs();
if (Array.isArray(iterable) || Type.string(iterable)) {
Array.prototype.forEach.call(iterable, function (entry) {
m.set(entry[0], entry[1]);
});
} else if (iterable instanceof Map) {
Map.prototype.forEach.call(iterable, function (value, key) {
m.set(key, value);
});
}
Object.setPrototypeOf(m, globals.Map.prototype);
defineProperty(m, 'constructor', Map, true);
return m;
};
globals.Map.prototype = create(OrigMapNoArgs.prototype);
Value.preserveToString(globals.Map, OrigMapNoArgs);
}
var m = new Map();
var mapUsesSameValueZero = (function (m) {
m['delete'](0);
m['delete'](-0);
m.set(0, 3);
m.get(-0, 4);
return m.get(0) === 3 && m.get(-0) === 4;
}(m));
var mapSupportsChaining = m.set(1, 2) === m;
if (!mapUsesSameValueZero || !mapSupportsChaining) {
var origMapSet = Map.prototype.set;
defineProperty(Map.prototype, 'set', function set(k, v) {
origMapSet.call(this, k === 0 ? 0 : k, v);
return this;
}, true);
Value.preserveToString(Map.prototype.set, origMapSet);
}
if (!mapUsesSameValueZero) {
var origMapGet = Map.prototype.get;
var origMapHas = Map.prototype.has;
defineProperties(Map.prototype, {
get: function get(k) {
return origMapGet.call(this, k === 0 ? 0 : k);
},
has: function has(k) {
return origMapHas.call(this, k === 0 ? 0 : k);
}
}, true);
Value.preserveToString(Map.prototype.get, origMapGet);
Value.preserveToString(Map.prototype.has, origMapHas);
}
var s = new Set();
var setUsesSameValueZero = (function (s) {
s['delete'](0);
s.add(-0);
return !s.has(0);
}(s));
var setSupportsChaining = s.add(1) === s;
if (!setUsesSameValueZero || !setSupportsChaining) {
var origSetAdd = Set.prototype.add;
Set.prototype.add = function add(v) {
origSetAdd.call(this, v === 0 ? 0 : v);
return this;
};
Value.preserveToString(Set.prototype.add, origSetAdd);
}
if (!setUsesSameValueZero) {
var origSetHas = Set.prototype.has;
Set.prototype.has = function has(v) {
return origSetHas.call(this, v === 0 ? 0 : v);
};
Value.preserveToString(Set.prototype.has, origSetHas);
var origSetDel = Set.prototype['delete'];
Set.prototype['delete'] = function SetDelete(v) {
return origSetDel.call(this, v === 0 ? 0 : v);
};
Value.preserveToString(Set.prototype['delete'], origSetDel);
}
var mapSupportsSubclassing = supportsSubclassing(globals.Map, function (M) {
var m = new M([]);
// Firefox 32 is ok with the instantiating the subclass but will
// throw when the map is used.
m.set(42, 42);
return m instanceof M;
});
var mapFailsToSupportSubclassing = Object.setPrototypeOf && !mapSupportsSubclassing; // without Object.setPrototypeOf, subclassing is not possible
var mapRequiresNew = (function () {
try {
return !(globals.Map() instanceof globals.Map);
} catch (e) {
return e instanceof TypeError;
}
}());
if (globals.Map.length !== 1 || mapFailsToSupportSubclassing || !mapRequiresNew) {
var OrigMap = globals.Map;
globals.Map = function Map(iterable) {
if (!(this instanceof Map)) {
throw new TypeError('Constructor Map requires "new"');
}
var m = new OrigMap(iterable);
Object.setPrototypeOf(m, Map.prototype);
defineProperty(m, 'constructor', Map, true);
return m;
};
globals.Map.prototype = create(OrigMap.prototype);
Value.preserveToString(globals.Map, OrigMap);
}
var setSupportsSubclassing = supportsSubclassing(globals.Set, function (S) {
var s = new S([]);
s.add(42, 42);
return s instanceof S;
});
var setFailsToSupportSubclassing = Object.setPrototypeOf && !setSupportsSubclassing; // without Object.setPrototypeOf, subclassing is not possible
var setRequiresNew = (function () {
try {
return !(globals.Set() instanceof globals.Set);
} catch (e) {
return e instanceof TypeError;
}
}());
if (globals.Set.length !== 1 || setFailsToSupportSubclassing || !setRequiresNew) {
var OrigSet = globals.Set;
globals.Set = function Set(iterable) {
if (!(this instanceof Set)) {
throw new TypeError('Constructor Set requires "new"');
}
var s = new OrigSet(iterable);
Object.setPrototypeOf(s, Set.prototype);
defineProperty(s, 'constructor', Set, true);
return s;
};
globals.Set.prototype = create(OrigSet.prototype);
Value.preserveToString(globals.Set, OrigSet);
}
var mapIterationThrowsStopIterator = !(function () {
var m = new Map();
try {
return m.keys().next().done;
} catch (e) {
return false;
}
}());
/*
- In Firefox < 23, Map#size is a function.
- In all current Firefox, Set#entries/keys/values & Map#clear do not exist
Expand All @@ -2429,16 +2585,16 @@
typeof globals.Set.prototype.forEach !== 'function' ||
isCallableWithoutNew(globals.Map) ||
isCallableWithoutNew(globals.Set) ||
!supportsSubclassing(globals.Map, function (M) {
var m = new M([]);
// Firefox 32 is ok with the instantiating the subclass but will
// throw when the map is used.
m.set(42, 42);
return m instanceof M;
})
typeof (new globals.Map().keys().next) !== 'function' || // Safari 8
mapIterationThrowsStopIterator || // Firefox 25
!mapSupportsSubclassing
) {
globals.Map = collectionShims.Map;
globals.Set = collectionShims.Set;
delete globals.Map; // necessary to overwrite in Safari 8
delete globals.Set; // necessary to overwrite in Safari 8
defineProperties(globals, {
Map: collectionShims.Map,
Set: collectionShims.Set
}, true);
}
}
if (globals.Set.prototype.keys !== globals.Set.prototype.values) {
Expand Down

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