182 lines
5.7 KiB
JavaScript
182 lines
5.7 KiB
JavaScript
// stringset.js
|
|
// MIT licensed, see LICENSE file
|
|
// Copyright (c) 2013 Olov Lassus <olov.lassus@gmail.com>
|
|
|
|
var StringSet = (function() {
|
|
"use strict";
|
|
|
|
// to save us a few characters
|
|
var hasOwnProperty = Object.prototype.hasOwnProperty;
|
|
|
|
var create = (function() {
|
|
function hasOwnEnumerableProps(obj) {
|
|
for (var prop in obj) {
|
|
if (hasOwnProperty.call(obj, prop)) {
|
|
return true;
|
|
}
|
|
}
|
|
return false;
|
|
}
|
|
|
|
// FF <= 3.6:
|
|
// o = {}; o.hasOwnProperty("__proto__" or "__count__" or "__parent__") => true
|
|
// o = {"__proto__": null}; Object.prototype.hasOwnProperty.call(o, "__proto__" or "__count__" or "__parent__") => false
|
|
function hasOwnPollutedProps(obj) {
|
|
return hasOwnProperty.call(obj, "__count__") || hasOwnProperty.call(obj, "__parent__");
|
|
}
|
|
|
|
var useObjectCreate = false;
|
|
if (typeof Object.create === "function") {
|
|
if (!hasOwnEnumerableProps(Object.create(null))) {
|
|
useObjectCreate = true;
|
|
}
|
|
}
|
|
if (useObjectCreate === false) {
|
|
if (hasOwnEnumerableProps({})) {
|
|
throw new Error("StringSet environment error 0, please file a bug at https://github.com/olov/stringset/issues");
|
|
}
|
|
}
|
|
// no throw yet means we can create objects without own enumerable props (safe-guard against VMs and shims)
|
|
|
|
var o = (useObjectCreate ? Object.create(null) : {});
|
|
var useProtoClear = false;
|
|
if (hasOwnPollutedProps(o)) {
|
|
o.__proto__ = null;
|
|
if (hasOwnEnumerableProps(o) || hasOwnPollutedProps(o)) {
|
|
throw new Error("StringSet environment error 1, please file a bug at https://github.com/olov/stringset/issues");
|
|
}
|
|
useProtoClear = true;
|
|
}
|
|
// no throw yet means we can create objects without own polluted props (safe-guard against VMs and shims)
|
|
|
|
return function() {
|
|
var o = (useObjectCreate ? Object.create(null) : {});
|
|
if (useProtoClear) {
|
|
o.__proto__ = null;
|
|
}
|
|
return o;
|
|
};
|
|
})();
|
|
|
|
// stringset ctor
|
|
function stringset(optional_array) {
|
|
// use with or without new
|
|
if (!(this instanceof stringset)) {
|
|
return new stringset(optional_array);
|
|
}
|
|
this.obj = create();
|
|
this.hasProto = false; // false (no __proto__ item) or true (has __proto__ item)
|
|
|
|
if (optional_array) {
|
|
this.addMany(optional_array);
|
|
}
|
|
};
|
|
|
|
// primitive methods that deals with data representation
|
|
stringset.prototype.has = function(item) {
|
|
// The type-check of item in has, get, set and delete is important because otherwise an object
|
|
// {toString: function() { return "__proto__"; }} can avoid the item === "__proto__" test.
|
|
// The alternative to type-checking would be to force string conversion, i.e. item = String(item);
|
|
if (typeof item !== "string") {
|
|
throw new Error("StringSet expected string item");
|
|
}
|
|
return (item === "__proto__" ?
|
|
this.hasProto :
|
|
hasOwnProperty.call(this.obj, item));
|
|
};
|
|
|
|
stringset.prototype.add = function(item) {
|
|
if (typeof item !== "string") {
|
|
throw new Error("StringSet expected string item");
|
|
}
|
|
if (item === "__proto__") {
|
|
this.hasProto = true;
|
|
} else {
|
|
this.obj[item] = true;
|
|
}
|
|
};
|
|
|
|
stringset.prototype.remove = function(item) {
|
|
if (typeof item !== "string") {
|
|
throw new Error("StringSet expected string item");
|
|
}
|
|
var didExist = this.has(item);
|
|
if (item === "__proto__") {
|
|
this.hasProto = false;
|
|
} else {
|
|
delete this.obj[item];
|
|
}
|
|
return didExist;
|
|
};
|
|
|
|
// alias remove to delete but beware:
|
|
// ss.delete("key"); // OK in ES5 and later
|
|
// ss['delete']("key"); // OK in all ES versions
|
|
// ss.remove("key"); // OK in all ES versions
|
|
stringset.prototype['delete'] = stringset.prototype.remove;
|
|
|
|
stringset.prototype.isEmpty = function() {
|
|
for (var item in this.obj) {
|
|
if (hasOwnProperty.call(this.obj, item)) {
|
|
return false;
|
|
}
|
|
}
|
|
return !this.hasProto;
|
|
};
|
|
|
|
stringset.prototype.size = function() {
|
|
var len = 0;
|
|
for (var item in this.obj) {
|
|
if (hasOwnProperty.call(this.obj, item)) {
|
|
++len;
|
|
}
|
|
}
|
|
return (this.hasProto ? len + 1 : len);
|
|
};
|
|
|
|
stringset.prototype.items = function() {
|
|
var items = [];
|
|
for (var item in this.obj) {
|
|
if (hasOwnProperty.call(this.obj, item)) {
|
|
items.push(item);
|
|
}
|
|
}
|
|
if (this.hasProto) {
|
|
items.push("__proto__");
|
|
}
|
|
return items;
|
|
};
|
|
|
|
|
|
// methods that rely on the above primitives
|
|
stringset.prototype.addMany = function(items) {
|
|
if (!Array.isArray(items)) {
|
|
throw new Error("StringSet expected array");
|
|
}
|
|
for (var i = 0; i < items.length; i++) {
|
|
this.add(items[i]);
|
|
}
|
|
return this;
|
|
};
|
|
|
|
stringset.prototype.merge = function(other) {
|
|
this.addMany(other.items());
|
|
return this;
|
|
};
|
|
|
|
stringset.prototype.clone = function() {
|
|
var other = stringset();
|
|
return other.merge(this);
|
|
};
|
|
|
|
stringset.prototype.toString = function() {
|
|
return "{" + this.items().map(JSON.stringify).join(",") + "}";
|
|
};
|
|
|
|
return stringset;
|
|
})();
|
|
|
|
if (typeof module !== "undefined" && typeof module.exports !== "undefined") {
|
|
module.exports = StringSet;
|
|
}
|