範例:where node
輸出:C:\Program Files\nodejs\node.exe

會特別找這個是因為我常更新某個command後,卻發現版本依然停在舊的,這時候用where就知道大概是哪個環境變數和舊版程式在搞鬼囉!
var o = {x: 1};
function foo(){
// Overwrite var `o` with a string
arguments[0] = "string";
}
foo(o);
console.log(o); // Why is `o` still an object and not the string `string`?
var o = {x: 1};
function foo(a){
// Overwrite var `o` with a string
a = "string";
}
foo(o);
console.log(o); // Why is `o` still an object and not the string `string`?