swc/crates/swc_bundler/tests/.cache/deno/eb373f5a8e59c75021b33eb6fc831e871e423dfb.ts
2021-11-09 20:42:49 +09:00

54 lines
1.5 KiB
TypeScript

// Loaded from https://deno.land/x/ramda@v0.27.2/source/mapAccum.js
import _curry3 from './internal/_curry3.js';
/**
* The `mapAccum` function behaves like a combination of map and reduce; it
* applies a function to each element of a list, passing an accumulating
* parameter from left to right, and returning a final value of this
* accumulator together with the new list.
*
* The iterator function receives two arguments, *acc* and *value*, and should
* return a tuple *[acc, value]*.
*
* @func
* @memberOf R
* @since v0.10.0
* @category List
* @sig ((acc, x) -> (acc, y)) -> acc -> [x] -> (acc, [y])
* @param {Function} fn The function to be called on every element of the input `list`.
* @param {*} acc The accumulator value.
* @param {Array} list The list to iterate over.
* @return {*} The final, accumulated value.
* @see R.scan, R.addIndex, R.mapAccumRight
* @example
*
* const digits = ['1', '2', '3', '4'];
* const appender = (a, b) => [a + b, a + b];
*
* R.mapAccum(appender, 0, digits); //=> ['01234', ['01', '012', '0123', '01234']]
* @symb R.mapAccum(f, a, [b, c, d]) = [
* f(f(f(a, b)[0], c)[0], d)[0],
* [
* f(a, b)[1],
* f(f(a, b)[0], c)[1],
* f(f(f(a, b)[0], c)[0], d)[1]
* ]
* ]
*/
var mapAccum = _curry3(function mapAccum(fn, acc, list) {
var idx = 0;
var len = list.length;
var result = [];
var tuple = [acc];
while (idx < len) {
tuple = fn(tuple[0], list[idx]);
result[idx] = tuple[1];
idx += 1;
}
return [tuple[0], result];
});
export default mapAccum;