Expect to have a property or method to get the number of characters in the string

[fanerge]

String.prototype.length
This property returns the number of code units in the string. UTF-16, the string format used by JavaScript, uses a single 16-bit code unit to represent the most common characters, but needs to use two code units for less commonly-used characters, so it's possible for the value returned by length to not match the actual number of characters in the string.
MDN-String.prototype.length

let num1 = '𠮷𠮷𠮷𠮷'.length; // 8
let num2 = '𠮷𠮷𠮷𠮷'.charCount; // 4 (Method similar to the number of statistical characters)

It is expected that there is a way to return the format of a character in a string instead of the number of UTF-16 coding units.

[ljharb]

Despite your expectations, there isn’t a direct way - you can use [...str].length though as a workaround. (A string’s length is the number of code units, not the number of code points)

If you’d like to suggest a new feature, please see https://github.com/tc39/ecma262/blob/master/CONTRIBUTING.md#creating-a-new-proposal

[claudepache]

What is a “character”? Given the complexity of Unicode, that need first to define precisely what you want .

@ljharb You gave a way to count the number of code points. However, a grapheme cluster is much closer of what is informally called a “character”... although it is not clear whether the OP actually knew that either.

[fanerge]

Despite your expectations, there isn’t a direct way - you can use [...str].length though as a workaround. (A string’s length is the number of code units, not the number of code points)

If you’d like to suggest a new feature, please see https://github.com/tc39/ecma262/blob/master/CONTRIBUTING.md#creating-a-new-proposal

thanks！
I think String's prototype chain should provide a method or property that counts the number of characters（code points） in a string. It shouldn't be converted to an array, using the length property of the array.
I will apply for this feature as you said.