以下源代码是什么编程语言？

Question

我现在所拥有的只是互联网。无法安装工具，也不知道如何搜索我的问题。

以下源代码是什么编程语言？

let parse = (S, nfa, str, idx=0) => {
    let stack = [nfa]
    let shift = () => {
        let next = stack[0].next(str.charAt(idx))
        if(next.size == 0) return false
        stack.unshift( [...next].reduce(plus, zero) )
        idx++
        return true
    }
    let reduce = () => {
        let reductions = stack[0].done()
        if(reductions.size == 0) return false
        if(reductions.size > 1) throw "Reduce/Reduce conflict"
        let {n, id} = [...reductions][0]
        while(0 < n--) stack.shift()
        stack.unshift( [...stack[0].next(id)].reduce(plus, zero))
        return true
    }
    while(idx < str.length) {
        if(!(shift() || reduce())) return false
    }
    do {
        if([...stack[0].done()].some(
            ({n,id}) => id == S && n == stack.length-1)) {
            return true
        }
    } while(reduce())
    return false
}