如何反轉“String.fromCodePoint”，即將字符串轉換為代碼點數組？

Question

String.fromCodePoint(...[127482, 127480])給了我一面美國國旗 ()。

如何將標志轉回[127482, 127480] ？

Answer 1

您正在尋找codePointAt ，可能使用 spread （等）轉換回數組，然后映射它們中的每一個。

console.log(theString.codePointAt(0)); // 127482
console.log(theString.codePointAt(2)); // 127480
// Note −−−−−−−−−−−−−−−−−−−−−−−−−−^
// It's 2 because the first code point in the string occupies two code *units*

或者

const array = [...theString].map(s => s.codePointAt(0));
console.log(array); // [127482, 127480]

或者像 Sebastian Simon 通過Array.from及其映射回調指出的那樣跳過一個中間步驟：

const array = Array.from(theString, s => s.codePointAt(0));
console.log(array); // [127482, 127480]

例子：

 const theString = String.fromCodePoint(...[127482, 127480]); console.log(theString.codePointAt(0)); // 127482 console.log(theString.codePointAt(2)); // 127480 const array = [...theString].map(s => s.codePointAt(0)); console.log(array); // [127482, 127480] const array2 = Array.from(theString, s => s.codePointAt(0)); console.log(array2); // [127482, 127480]

Spread 和Array.from都使用字符串迭代器工作，它通過代碼點工作，而不是像大多數字符串方法那樣工作的代碼單元。