JS实现斐波那契数列的五种方式

function fibonacci(n){
var res1 = 1;
var res2 = 1;
var sum = res2;
for(var i = 1;i < n;i ++){
sum = res1 + res2;
res1 = res2;
res2 = sum;
}
return sum;
}

function fibonacci (n) {
if ( n <= 1 ) {return 1};
return fibonacci(n - 1) + fibonacci(n - 2);
}

function fibonacci(n, ac1=1,ac2=1){
if(n<=1){return ac2}
return fibonacci(n-1, ac2, ac1 + ac2)
}
Generator 函数和for...of循环
// Generator 函数和for...of循环
function* fibonacci() {
let [prev, curr] = [0, 1];
　　// foo(;;)相当于死循环 等于while(1)
for (;;) {
yield curr;
[prev, curr] = [curr, prev + curr];
}
}
for (let n of fibonacci()) {
if (n > 1000) break;
console.log(n);
}

const fibonacci = function(){
var mem = [0,1];
var f = function(n){
var res = mem[n];
if(typeof res !== "number"){
mem[n] = f(n-1) + f(n-2);
res = mem[n];
}
return res;
}
return f;
}();