尾调用优化 (TCO) 在 Safari 中不起作用

Question

根据ES6 compatibility table，Safari 有尾调用优化功能。试过了，它像任何其他浏览器一样失败。我错过了什么吗？

function factorial(n, r = 1n) {
  return (n <= 1) ? r : factorial(n - 1n, n * r)
}

console.log(factorial(36000n))

Safari 输出：

RangeError: Maximum call stack size exceeded.

Answer 1

您需要运行您的程序处于严格模式。

"use strict";

function factorial(n, r = 1n) {
    return n <= 1n ? r : factorial(n - 1n, n * r);
}

console.log(factorial(36000n).toString());

要将函数调用视为正确的尾调用，需要满足四个条件。

The calling function is in strict mode.

The calling function is either a normal function or an arrow function.

The calling function is not a generator function.

The return value of the called function is returned by the calling function.

来源：ECMAScript 6 Proper Tail Calls in WebKit by Michael Saboff

尾调用优化 (TCO) 在 Safari 中不起作用

Tail call optimization (TCO) not working in Safari

javascript

recursion

functional-programming

safari

tail-recursion