javascript - Why can't variables be used for js array key names? What should I do if I want to use variables as associative array keys like PHP?

Question

When using the key name, an error is reported saying that the set property cannot be set

Answer 1

JS Object

var o = {
    name: 'foo', 
    hey: 'bar'
}
console.log(o.name); 
// => "foo"
console.log(o['name']); 
// => "foo"

Map object

The above-mentioned ordinary js objects can only use strings as keys. es6 has a new feature that allows "value" to be used as the key. See example:

var m = new Map(); 

var eczn = {
    name: 'eczn',
    age: 20
}

m.set(eczn, 'map Obj to Stirng'); 

console.log(m); 

Answer 2

Arrays in JavaScript do not support using identifiers other than numbers as array subscripts, but you can use objects to achieve similar effects to associative arrays in PHP:

var myArray = {'key1': 'value1'};
console.log(myArray['key1']); // 会输出value1, 其实相当于myArray.key1

Answer 3

JS arrays use custom key names, which I have never used in development for so long. There is no need for it at all. Just use Object.

Answer 4

Yes, for example

var person = {
    "name" : "孤月"
};

var n = "name";

console.log(person[n]);
//设置键名
person[n] = "deep dark fantasy";

Answer 5

Original arrays cannot use characters other than numbers as key names. You can use objects as arrays to achieve the same functionality.

Answer 6

When defined, arrays can only be indexed by numbers, for example, while other types of index are objects. This is different from php.

Answer 7

JS does not have associative arrays, only basic arrays. What looks like associative arrays are objects. This js has them.

Answer 8

JS arrays can be subscripted with strings. Similar to associative arrays, the type of array subscript in JS is strings