const chunk = ( horizon, principal, roi, recyear, recseverity ) => { 
	return new Promise( resolve => {
		// Decimalise and create portfolio holder
		let portfolio = principal
		let crash = 1 - ( recseverity / 100 )
		let grow = 1 + ( roi / 100 )

		// Loop over the years and crash or grow
		for (let thisyear = 1; thisyear < horizon +1; thisyear++) {
			thisyear == recyear ? ( portfolio *= crash ) : ( portfolio *= grow )
			console.log( portfolio )
		}
		console.log( 'last', portfolio )

		// Resolve with the outcome
		resolve( { year: recyear, result: portfolio } )
	} )
}

const horizon = 20
const principal = 100
const roi = 7
const recseverity = 50
const yearlyadd = principal/horizon

const recessions = []
for (let year = 1; year < horizon +1; year++) {
	recessions.push( { year: year, severity: recseverity } )
}

Promise.all( recessions.map( recession => chunk( horizon, principal, roi, recession.year, recession.severity ) ) )
.then( console.log.bind( console ) )

回答如下：

我的假设是错误的。

我假设在复利计算中，投资组合减半的年份很重要。

在现实世界中：我认为如果你投资X金额，那么明年或10年是否会出现衰退就很重要。

事实证明它没有。

PBKAC。

非常感谢那些帮助我得出这个结论的人。