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Created July 9, 2011 12:02
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The sample usage of ECMA 5 Features Implemented in V8
/**
* The sample usage of ECMA 5 Mozilla Features Implemented in V8
* https://github.com/joyent/node/wiki/ECMA-5-Mozilla-Features-Implemented-in-V8
* You can use thease new feature of ECMA5 on Node.js as you like.
* because there is no IE :)
* Order is deferent form original wiki.
* Sources are Checked on Node.js v0.5.0(unstable), v0.4.9(stable)
*
* you can execute this file.
* $ node ecma5_on_v8.js
*
* @author Jxck
* @license http://www.opensource.org/licenses/mit-license.php (The MIT License).
*/
// console.log is tooooooo long :(
var log = console.log;
log('---- Object -----');
var obj = {
_str: 'default',
get str() { // getter
return this._str + '!';
},
set str(val) { // setter
this._str = val.trim();
}
};
log(obj.str); // "default!"
obj.str = ' asdf ';
log(obj.str); // "asdf!"
log('---- Object.defineProperty(obj, prop, desc) ----');
var obj = {};
Object.defineProperty(obj, 'num', {
value: 10,
writable: false,
enumerable: false,
configurable: false
});
log(obj.num); // 10
for (var i in obj) {
log(i); // not display
}
obj.num = 20;
log(obj.num); // still 10
log('---- Object.defineProperties(obj, props) ----');
var obj = {};
Object.defineProperties(obj, {
num: {
value: 4,
writable: false,
enumerable: false,
configurable: false
},
root: {
get: function() {
return Math.pow(this.num, 0.5);
}
}
});
log(obj.num); // 4
log(obj.root); // 2
log('---- Object.create(proto, props) ----');
// extends x, y
var obj = Object.create({x: 10, y: 20});
log(obj.x); // 10
log(obj.y); // 20
var obj = Object.create(null);
log(obj); // not extend anything
var obj = Object.create(Object.prototype);
log(obj); // same as {} , new Object()
var obj = Object.create({x: 10, y: 20}, {
z: {
value: 30,
writable: true
},
sum: {
get: function() {
return this.x + this.y + this.z;
}
}
});
log(obj.x); // 10
log(obj.y); // 20
log(obj.z); // 30
log(obj.sum); // 60
log('---- Object.keys(obj) ----');
function o() {
this.a = 1;
}
log(Object.keys(new o())); // [ 'a' ]
function p() {
this.b = 2;
}
p.prototype = new o();
log(Object.keys(new p())); // [ 'b' ]
var obj = Object.create({a: 10, b: 20}, {
x: {
value: 30,
enumerable: true
},
y: {
value: 40,
enumerable: false
}
});
log(Object.keys(obj)); // [ 'x' ]
log('---- Object.getOwnPropertyNames(obj) ----');
var obj = Object.create({a: 10, b: 20}, {
x: {
value: 30,
enumerable: true
},
y: {
value: 40,
enumerable: false
}
});
log(Object.getOwnPropertyNames(obj)); // [ 'y', 'x' ]
log('---- Object.getPrototypeOf(obj) ----');
var obj = Object.create({a: 10, b: 20}, {
x: {
value: 30,
enumerable: true
},
y: {
value: 40,
enumerable: false
}
});
log(Object.getPrototypeOf(obj)); // { a: 10, b: 20 }
log('---- Object.getOwnPropertyDescriptor(obj, property) ----');
var obj = Object.create({a: 10, b: 20}, {
x: {
value: 30,
enumerable: true
},
y: {
value: 40,
enumerable: false
}
});
log(Object.getOwnPropertyDescriptor(obj, 'x'));
// { value: 30,
// writable: false,
// enumerable: true,
// configurable: false }
log('---- Object.preventExtensions(obj) ----');
var obj = {a: 10, b: 20};
Object.preventExtensions(obj);
// obj.x = 30; // TypeError: Can't add property x, object is not extensible
log('---- Object.isExtensible(obj) ----');
var obj = {a: 10, b: 20};
log(Object.isExtensible(obj)); // true
Object.preventExtensions(obj);
log(Object.isExtensible(obj)); // false
log('---- Object.seal(obj) ----');
var obj = {a: 10, b: 20};
Object.seal(obj);
obj.a = 30;
log(obj.a); // 30
// obj.x = 30; // TypeError: Can't add property x, object is not extensible
log('---- Object.isSealed(obj) ----');
var obj = {a: 10, b: 20};
Object.seal(obj);
log(Object.isSealed(obj)); // true
log('---- Object.freeze(obj) ----');
var obj = {a: 10, b: 20};
Object.freeze(obj);
obj.a = 30;
log(obj.a); // 10
log('---- Object.isFrozen(obj) ----');
var obj = {a: 10, b: 20};
Object.freeze(obj);
log(Object.isFrozen(obj)); // true
log('---- isPrototypeOf(obj) ----');
var proto = {a: 10, b: 20};
var obj = Object.create(proto);
log(proto.isPrototypeOf(obj)); // true
log('---- bind(thisArg[, arg1[, argN]]) ----');
var f = function() {
return this.a + this.b;
};
log(f()); // NaN
var g = f.bind({ a: 10, b: 20 });
log(g()); // 30
var f = function(c) {
return this.a + this.b + c;
};
log(f()); // NaN
var g = f.bind({ a: 10, b: 20 }, 30);
log(g()); // 60
var f = function(c, d) {
return this.a + this.b + c + d;
};
log(f()); // NaN
var g = f.bind({ a: 10, b: 20 }, 30);
log(g(40)); // 100
log('---- JSON.stringify(obj [, replacer [, space]]) ----');
log(JSON.stringify({ a: 1 }));
log(JSON.stringify([1, 2, 3], function replacer(key, value) {
if (!Array.isArray(value)) {
return value;
}
var len = value.length;
var result = { length: len };
for (var i = 0; i < len; ++i) {
result[i] = value[i];
}
return result;
}));
log(JSON.stringify({ a: 1, b: 2}, null, 2));
log(JSON.stringify({ a: 1, b: 2}, null, 4));
log(JSON.stringify({ a: 1, b: 2}, null, '\t'));
log('---- JSON.parse(string) ----');
var s = JSON.stringify({ a: 1, b: 0 });
log(JSON.parse(s));
log(
JSON.parse(s, function(key, value) {
if (value === 0)
value = false;
else if (value === 1) {
value = true;
}
return value;
})
);
log('---- trim(), trimRight(), trimLeft() ----');
log(' abc '.trim());
log(' abc '.trimRight());
log(' abc '.trimLeft());
log('---- Array.isArray(array) ----');
log(Array.isArray([]));
log('---- indexOf(value) ----');
log(([1, 2, 2, 3]).indexOf(2));
log('---- lastIndexOf(value) ----');
log(([1, 2, 2, 3]).lastIndexOf(2));
log('---- filter(callback) ----');
log(
([1, 2, 3, 4]).filter(function(x) {
return x > 2;
})
);
log('---- forEach(callback) ----');
([1, 2, 3]).forEach(function(x) {
log(x * 2);
});
log('---- every(callback) ----');
log(
([1, 2, 3]).every(function(x) {
return x > 0;
})
);
log(
([1, 2, 3]).every(function(x) {
return x > 1;
})
);
log('---- some(callback) ----');
log(
([1, 2, 3]).some(function(x) {
return x > 2;
})
);
log(
([1, 2, 3]).some(function(x) {
return x > 3;
})
);
log('---- map(callback) ----');
log(
([1, 2, 3]).map(function(x) {
return x * 2;
})
);
log('---- reduce(callback[, initialValue]) ----');
log(
(['a', 'b', 'c']).reduce(function(x, y) {
return x + y;
})
);
log(
(['a', 'b', 'c']).reduce(function(x, y) {
return x + y;
}, '*')
);
log('---- reduceRight(callback[, initialValue]) ----');
log(
(['a', 'b', 'c']).reduceRight(function(x, y) {
return x + y;
})
);
log(
(['a', 'b', 'c']).reduceRight(function(x, y) {
return x + y;
}, '*')
);
log('---- Date.now() ----');
log(Date.now());
log('---- toISOString() ----');
log((new Date()).toISOString());
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