in Events and Hacks/Tech Talks/ContainerDemo/example-voting-app/result/views/socket.io.js [6150:6278]
function has(name) {
if (has[name] !== undef) {
// Return cached feature test result.
return has[name];
}
var isSupported;
if (name == "bug-string-char-index") {
// IE <= 7 doesn't support accessing string characters using square
// bracket notation. IE 8 only supports this for primitives.
isSupported = "a"[0] != "a";
} else if (name == "json") {
// Indicates whether both `JSON.stringify` and `JSON.parse` are
// supported.
isSupported = has("json-stringify") && has("json-parse");
} else {
var value, serialized = '{"a":[1,true,false,null,"\\u0000\\b\\n\\f\\r\\t"]}';
// Test `JSON.stringify`.
if (name == "json-stringify") {
var stringify = JSON3.stringify, stringifySupported = typeof stringify == "function" && isExtended;
if (stringifySupported) {
// A test function object with a custom `toJSON` method.
(value = function () {
return 1;
}).toJSON = value;
try {
stringifySupported =
// Firefox 3.1b1 and b2 serialize string, number, and boolean
// primitives as object literals.
stringify(0) === "0" &&
// FF 3.1b1, b2, and JSON 2 serialize wrapped primitives as object
// literals.
stringify(new Number()) === "0" &&
stringify(new String()) == '""' &&
// FF 3.1b1, 2 throw an error if the value is `null`, `undefined`, or
// does not define a canonical JSON representation (this applies to
// objects with `toJSON` properties as well, *unless* they are nested
// within an object or array).
stringify(getClass) === undef &&
// IE 8 serializes `undefined` as `"undefined"`. Safari <= 5.1.7 and
// FF 3.1b3 pass this test.
stringify(undef) === undef &&
// Safari <= 5.1.7 and FF 3.1b3 throw `Error`s and `TypeError`s,
// respectively, if the value is omitted entirely.
stringify() === undef &&
// FF 3.1b1, 2 throw an error if the given value is not a number,
// string, array, object, Boolean, or `null` literal. This applies to
// objects with custom `toJSON` methods as well, unless they are nested
// inside object or array literals. YUI 3.0.0b1 ignores custom `toJSON`
// methods entirely.
stringify(value) === "1" &&
stringify([value]) == "[1]" &&
// Prototype <= 1.6.1 serializes `[undefined]` as `"[]"` instead of
// `"[null]"`.
stringify([undef]) == "[null]" &&
// YUI 3.0.0b1 fails to serialize `null` literals.
stringify(null) == "null" &&
// FF 3.1b1, 2 halts serialization if an array contains a function:
// `[1, true, getClass, 1]` serializes as "[1,true,],". FF 3.1b3
// elides non-JSON values from objects and arrays, unless they
// define custom `toJSON` methods.
stringify([undef, getClass, null]) == "[null,null,null]" &&
// Simple serialization test. FF 3.1b1 uses Unicode escape sequences
// where character escape codes are expected (e.g., `\b` => `\u0008`).
stringify({ "a": [value, true, false, null, "\x00\b\n\f\r\t"] }) == serialized &&
// FF 3.1b1 and b2 ignore the `filter` and `width` arguments.
stringify(null, value) === "1" &&
stringify([1, 2], null, 1) == "[\n 1,\n 2\n]" &&
// JSON 2, Prototype <= 1.7, and older WebKit builds incorrectly
// serialize extended years.
stringify(new Date(-8.64e15)) == '"-271821-04-20T00:00:00.000Z"' &&
// The milliseconds are optional in ES 5, but required in 5.1.
stringify(new Date(8.64e15)) == '"+275760-09-13T00:00:00.000Z"' &&
// Firefox <= 11.0 incorrectly serializes years prior to 0 as negative
// four-digit years instead of six-digit years. Credits: @Yaffle.
stringify(new Date(-621987552e5)) == '"-000001-01-01T00:00:00.000Z"' &&
// Safari <= 5.1.5 and Opera >= 10.53 incorrectly serialize millisecond
// values less than 1000. Credits: @Yaffle.
stringify(new Date(-1)) == '"1969-12-31T23:59:59.999Z"';
} catch (exception) {
stringifySupported = false;
}
}
isSupported = stringifySupported;
}
// Test `JSON.parse`.
if (name == "json-parse") {
var parse = JSON3.parse;
if (typeof parse == "function") {
try {
// FF 3.1b1, b2 will throw an exception if a bare literal is provided.
// Conforming implementations should also coerce the initial argument to
// a string prior to parsing.
if (parse("0") === 0 && !parse(false)) {
// Simple parsing test.
value = parse(serialized);
var parseSupported = value["a"].length == 5 && value["a"][0] === 1;
if (parseSupported) {
try {
// Safari <= 5.1.2 and FF 3.1b1 allow unescaped tabs in strings.
parseSupported = !parse('"\t"');
} catch (exception) {}
if (parseSupported) {
try {
// FF 4.0 and 4.0.1 allow leading `+` signs and leading
// decimal points. FF 4.0, 4.0.1, and IE 9-10 also allow
// certain octal literals.
parseSupported = parse("01") !== 1;
} catch (exception) {}
}
if (parseSupported) {
try {
// FF 4.0, 4.0.1, and Rhino 1.7R3-R4 allow trailing decimal
// points. These environments, along with FF 3.1b1 and 2,
// also allow trailing commas in JSON objects and arrays.
parseSupported = parse("1.") !== 1;
} catch (exception) {}
}
}
}
} catch (exception) {
parseSupported = false;
}
}
isSupported = parseSupported;
}
}
return has[name] = !!isSupported;
}