import { __TS__CountVarargs } from "./CountVarargs";
// https://www.ecma-international.org/ecma-262/9.0/index.html#sec-array.prototype.reduce
export function __TS__ArrayReduce(
this: TElement[],
callbackFn: (accumulator: TAccumulator, currentValue: TElement, index: number, array: TElement[]) => TAccumulator,
...initial: TAccumulator[]
): TAccumulator {
const len = this.length;
let k = 0;
let accumulator: TAccumulator = undefined!;
// Check if initial value is present in function call
if (__TS__CountVarargs(...initial) !== 0) {
[accumulator] = [...initial];
} else if (len > 0) {
accumulator = this[0] as unknown as TAccumulator;
k = 1;
} else {
throw "Reduce of empty array with no initial value";
}
for (const i of $range(k + 1, len)) {
accumulator = callbackFn(accumulator, this[i - 1], i - 1, this);
}
return accumulator;
}