Node.js/JavaScript 内置类型的存根？
这个练习相当学术化，但它对于理解 JavaScript 的行为很有用。
为什么这个可行：
var fs = require('fs');
console.log(fs.readdirSync('/').length); //approximately '28' on my Macbook
fs['readdirSync'] = function(){ return ['/tmp', '/bin']; };
console.log(fs.readdirSync('/').length); //'2' as expected
而这个不行：
var a = "hello world";
console.log(a.length); //'11'
a['length'] = 1000;
console.log(a.length); //still '11'... why??
我知道可以对 JavaScript 内置类型（例如 String）进行 Monkeypatch，但是是否可以对它们进行存根？
提前致谢。
This exercise is fairly academic, but it's useful in understanding JavaScript's behavior.
Why does this work:
var fs = require('fs');
console.log(fs.readdirSync('/').length); //approximately '28' on my Macbook
fs['readdirSync'] = function(){ return ['/tmp', '/bin']; };
console.log(fs.readdirSync('/').length); //'2' as expected
and this doesn't:
var a = "hello world";
console.log(a.length); //'11'
a['length'] = 1000;
console.log(a.length); //still '11'... why??
I know it's possible to monkeypatch JavaScript built-in types such as String, but is it possible to stub them?
Thanks in advance.
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由 TJ Holowaychuk 提供：字符串是不可变的。所以看来以这种方式是不可能的。
Courtesy of TJ Holowaychuk: Strings are immutable. So it seems like it's not possible in this manner.