javascript - 如何将键/值对添加到JavaScript对象？(How can I add a key/value pair to a JavaScript object?)

Question

Here is my object literal:

(这是我的对象文字：)

var obj = {key1: value1, key2: value2};

How can I add {key3: value3} to the object?

(如何向对象添加{key3: value3} ？)

  ask by James Skidmore translate from so

Answer 1

There are two ways to add new properties to an object:

(有两种向对象添加新属性的方法：)

var obj = {
    key1: value1,
    key2: value2
};

Using dot notation: (使用点表示法：)

obj.key3 = "value3";

Using square bracket notation: (使用方括号表示法：)

obj["key3"] = "value3";

The first form is used when you know the name of the property.

(当您知道属性名称时，将使用第一种形式。)

The second form is used when the name of the property is dynamically determined.

(动态确定属性名称时，使用第二种形式。)

Like in this example:

(像这个例子：)

var getProperty = function (propertyName) {
    return obj[propertyName];
};

getProperty("key1");
getProperty("key2");
getProperty("key3");

---

A real JavaScript array can be constructed using either:

(可以使用以下任意一种来构造真实的 JavaScript数组：)

The Array literal notation: (数组文字表示法：)

var arr = [];

The Array constructor notation: (数组构造器符号：)

var arr = new Array();