`String.prototype.at` 并非在所有浏览器中都实现。 是否有 @babel/plugin 可以将其转换为 ES5 javascript？

Question

At the time of this question String.prototype.at is not implemented in all browsers.

I would like to use the at function on the String prototype within a React app that uses babel to transform modern ecmascript into older more browser compatible versions of javascript.

I have been unsuccessful in finding a babel plugin that would do this for me.

Is there a @babel/plugin that will transform the String prototype at function down to more browser compatible ES5 javascript?

Answer 1

String.prototype.at is equal this function

let text = "hello, how are you";
function at(a, b) {
    return a.charAt(b < 0 ? a.length-Math.abs(b) : b);
}
console.log(at(text, -3));
console.log(text.at(-3));

Answer 2

Babel is for syntax-level transformations, not browser API polyfills.

You can consider using a polyfill service like Polyfill.io , or alternatively, simply use the polyfill code from the relevant proposal .