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Map and Set methods are not generic, and must only be called on v…
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…alid `Map` and `Set` objects.
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@ljharb
ljharb committed Apr 27, 2015
1 parent 0fa4c96 commit d5b4031
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Showing 2 changed files with 54 additions and 4 deletions.
42 changes: 38 additions & 4 deletions es6-shim.js
View file
Expand Up @@ -1915,7 +1915,18 @@
return this.key === empty;
};

var isMap = function isMap(map) {
return !!map._es6map;
};

var requireMapSlot = function requireMapSlot(map, method) {
if (!ES.TypeIsObject(map) || !isMap(map)) {
throw new TypeError('Method Map.prototype.' + method + ' called on incompatible receiver ' + String(map));
}
};

function MapIterator(map, kind) {
requireMapSlot(map, '[[MapIterator]]');
this.head = map._head;
this.i = this.head;
this.kind = kind;
Expand Down Expand Up @@ -2008,6 +2019,7 @@

defineProperties(Map.prototype, {
get: function (key) {
requireMapSlot(this, 'get');
var fkey = fastkey(key);
if (fkey !== null) {
// fast O(1) path
Expand All @@ -2027,6 +2039,7 @@
},

has: function (key) {
requireMapSlot(this, 'has');
var fkey = fastkey(key);
if (fkey !== null) {
// fast O(1) path
Expand All @@ -2042,6 +2055,7 @@
},

set: function (key, value) {
requireMapSlot(this, 'set');
var head = this._head, i = head, entry;
var fkey = fastkey(key);
if (fkey !== null) {
Expand Down Expand Up @@ -2074,6 +2088,7 @@
},

'delete': function (key) {
requireMapSlot(this, 'delete');
var head = this._head, i = head;
var fkey = fastkey(key);
if (fkey !== null) {
Expand All @@ -2098,6 +2113,7 @@
},

clear: function clear() {
requireMapSlot(this, 'clear');
this._size = 0;
this._storage = emptyObject();
var head = this._head, i = head, p = i.next;
Expand All @@ -2110,18 +2126,22 @@
},

keys: function keys() {
requireMapSlot(this, 'keys');
return new MapIterator(this, 'key');
},

values: function values() {
requireMapSlot(this, 'values');
return new MapIterator(this, 'value');
},

entries: function entries() {
requireMapSlot(this, 'entries');
return new MapIterator(this, 'key+value');
},

forEach: function forEach(callback) {
requireMapSlot(this, 'forEach');
var context = arguments.length > 1 ? arguments[1] : null;
var it = this.entries();
for (var entry = it.next(); !entry.done; entry = it.next()) {
Expand All @@ -2139,6 +2159,16 @@
}()),

Set: (function () {
var isSet = function isSet(set) {
return set._es6set && typeof set._storage !== 'undefined';
};
var requireSetSlot = function requireSetSlot(set, method) {
if (!ES.TypeIsObject(set) || !isSet(set)) {
// https://github.com/paulmillr/es6-shim/issues/176
throw new TypeError('Set.prototype.' + method + ' called on incompatible receiver ' + String(set));
}
};

// Creating a Map is expensive. To speed up the common case of
// Sets containing only string or numeric keys, we use an object
// as backing storage and lazily create a full Map only when
Expand Down Expand Up @@ -2202,16 +2232,14 @@
};

Value.getter(SetShim.prototype, 'size', function () {
if (typeof this._storage === 'undefined') {
// https://github.com/paulmillr/es6-shim/issues/176
throw new TypeError('size method called on incompatible Set');
}
requireSetSlot(this, 'size');
ensureMap(this);
return this['[[SetData]]'].size;
});

defineProperties(SetShim.prototype, {
has: function (key) {
requireSetSlot(this, 'has');
var fkey;
if (this._storage && (fkey = fastkey(key)) !== null) {
return !!this._storage[fkey];
Expand All @@ -2221,6 +2249,7 @@
},

add: function (key) {
requireSetSlot(this, 'add');
var fkey;
if (this._storage && (fkey = fastkey(key)) !== null) {
this._storage[fkey] = true;
Expand All @@ -2232,6 +2261,7 @@
},

'delete': function (key) {
requireSetSlot(this, 'delete');
var fkey;
if (this._storage && (fkey = fastkey(key)) !== null) {
var hasFKey = _hasOwnProperty(this._storage, fkey);
Expand All @@ -2242,6 +2272,7 @@
},

clear: function clear() {
requireSetSlot(this, 'clear');
if (this._storage) {
this._storage = emptyObject();
} else {
Expand All @@ -2250,16 +2281,19 @@
},

values: function values() {
requireSetSlot(this, 'values');
ensureMap(this);
return this['[[SetData]]'].values();
},

entries: function entries() {
requireSetSlot(this, 'entries');
ensureMap(this);
return this['[[SetData]]'].entries();
},

forEach: function forEach(callback) {
requireSetSlot(this, 'forEach');
var context = arguments.length > 1 ? arguments[1] : null;
var entireSet = this;
ensureMap(entireSet);
Expand Down
16 changes: 16 additions & 0 deletions test/collections.js
View file
Expand Up @@ -292,6 +292,14 @@ describe('Collections', function () {
it('has the right arity', function () {
expect(Map.prototype.entries).to.have.property('length', 0);
});

it('throws when called on a non-Map', function () {
var expectedMessage = /^(Method )?Map.prototype.entries called on incompatible receiver |^entries method called on incompatible /;
var nonMaps = [true, false, 'abc', NaN, new Set([1, 2]), { a: true }, [1], Object('abc'), Object(NaN)];
nonMaps.forEach(function (nonMap) {
expect(function () { return Map.prototype.entries.call(nonMap); }).to['throw'](TypeError, expectedMessage);
});
});
});

it('should has unique constructor', function () {
Expand Down Expand Up @@ -748,6 +756,14 @@ describe('Collections', function () {
it('has the right arity', function () {
expect(Set.prototype.values).to.have.property('length', 0);
});

it('throws when called on a non-Set', function () {
var expectedMessage = /^(Method )?Set.prototype.values called on incompatible receiver |^values method called on incompatible /;
var nonSets = [true, false, 'abc', NaN, new Map([[1, 2]]), { a: true }, [1], Object('abc'), Object(NaN)];
nonSets.forEach(function (nonSet) {
expect(function () { return Set.prototype.values.call(nonSet); }).to['throw'](TypeError, expectedMessage);
});
});
});

describe('#entries()', function () {
Expand Down

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