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Structs in JS - http://bl.ocks.org/endash/125e9713c97b7c72d305
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <title>Struct</title> | |
| <link rel="stylesheet" href="http://code.jquery.com/qunit/qunit-1.15.0.css"> | |
| </head> | |
| <body> | |
| <div id="qunit"></div> | |
| <div id="qunit-fixture"></div> | |
| <script src="http://code.jquery.com/qunit/qunit-1.15.0.js"></script> | |
| <script src="struct.js"></script> | |
| <script src="struct-tests.js"></script> | |
| </body> | |
| </html> |
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| "use strict"; | |
| test("Can define a struct with arguments or an array", function () { | |
| var a, b; | |
| ok(a = Struct("a", "b", "c")); | |
| ok(b = Struct(["a", "b", "c"])); | |
| equal(a.attrs.length, 3); | |
| equal(b.attrs.length, 3); | |
| }); | |
| test("Cannot define an empty struct", function () { | |
| throws(function () { Struct(); }); | |
| throws(function () { Struct([]); }); | |
| }); | |
| test("Passed attributes must match the definition", function () { | |
| var struct = Struct("a", "b", "c"); | |
| throws(function () { new struct(); }); | |
| throws(function () { new struct({a: 5}); }); | |
| throws(function () { new struct({a: 5, b: 8, c: 9, d: 8}); }); | |
| }); | |
| test("Struct is frozen", function () { | |
| var struct = Struct("a", "b", "c"); | |
| var obj = new struct({a: 1, b: 2, c: 3}); | |
| throws(function () { obj.a = 5 }); | |
| }); | |
| test("Can read attributes from a struct", function () { | |
| var StructA = Struct("a", "b", "c"); | |
| equal((new StructA({a: 1, b: 2, c: 3})).a, 1); | |
| }); | |
| test("Anonymous struct toString", function () { | |
| var StructA = Struct("a"); | |
| equal(StructA.toString(), "Struct<a>"); | |
| }); | |
| test("Anonymous struct instance toString", function () { | |
| var StructA = Struct("a", "b"); | |
| var obj = new StructA({a: 1, b: 2}); | |
| equal(obj.toString(), "Struct<a=1,b=2>"); | |
| }); | |
| test("Named struct toString", function () { | |
| var StructA = Struct("name").named("Person"); | |
| equal(StructA.toString(), "Person<name>"); | |
| }); |
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| window.Struct = (function () { | |
| "use strict"; | |
| function arrayEquals(array1, array2) { | |
| if (array1.length != array2.length) { return false; } | |
| var i = 0, len = array1.length; | |
| for (i; i < len; i++) { | |
| if (array1[i] !== array2[i]) { return false; } | |
| } | |
| return true; | |
| } | |
| return function(attrNames) { | |
| if (arguments.length == 0) throw "Cannot define an empty struct"; | |
| if (attrNames.constructor != Array) { attrNames = Array.prototype.slice.call(arguments); } | |
| if (!attrNames.length) throw "Cannot define an empty struct"; | |
| var sortedAttrNames = attrNames.slice().sort(); | |
| var joinedAttrNames = sortedAttrNames.join(", "); | |
| var attrsLength = attrNames.length; | |
| var name = "Struct"; | |
| var func = function (attrs) { | |
| if (arguments.length == 0 || attrs.constructor != Object) throw "Must pass a hash of attributes to a Struct"; | |
| var keys = Object.keys(attrs).sort(); | |
| if (!arrayEquals(keys, sortedAttrNames)) { | |
| throw "Attributes (" + keys.join(", ") + ") do not match the struct factory definition (" + joinedAttrNames + ")"; | |
| } | |
| var i = 0; | |
| var attrName; | |
| for (i; i < attrsLength; i++) { | |
| attrName = attrNames[i]; | |
| this[attrName] = attrs[attrName]; | |
| } | |
| Object.freeze(this); | |
| } | |
| func.named = function (newName) { | |
| if (name != "Struct") throw "This Struct has already been named: '" + name + "'"; | |
| name = newName; | |
| return this; | |
| }; | |
| func.toString = function () { return name + "<" + joinedAttrNames + ">"; }; | |
| func.attrs = sortedAttrNames; | |
| func.prototype = { | |
| toString: function () { | |
| var attrStrings = [] | |
| for (var i = 0, attr; i < sortedAttrNames.length; i++) { | |
| attr = sortedAttrNames[i]; | |
| attrStrings.push(attr + "=" + this[attr]); | |
| } | |
| return name + "<" + attrStrings.join(",") + ">"; | |
| } | |
| }; | |
| return func; | |
| } | |
| })(); |
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