You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
49 lines
1.6 KiB
49 lines
1.6 KiB
2 years ago
|
'use strict';
|
||
|
|
// https://github.com/tc39/proposal-iterator-helpers
|
||
|
|
var $ = require('../internals/export');
|
||
|
|
var call = require('../internals/function-call');
|
||
|
|
var aCallable = require('../internals/a-callable');
|
||
|
|
var anObject = require('../internals/an-object');
|
||
|
|
var getBuiltIn = require('../internals/get-built-in');
|
||
|
|
|
||
|
|
var Promise = getBuiltIn('Promise');
|
||
|
|
var $TypeError = TypeError;
|
||
|
|
|
||
|
|
$({ target: 'AsyncIterator', proto: true, real: true, forced: true }, {
|
||
|
|
reduce: function reduce(reducer /* , initialValue */) {
|
||
|
|
var iterator = anObject(this);
|
||
|
|
var next = aCallable(iterator.next);
|
||
|
|
var noInitial = arguments.length < 2;
|
||
|
|
var accumulator = noInitial ? undefined : arguments[1];
|
||
|
|
aCallable(reducer);
|
||
|
|
|
||
|
|
return new Promise(function (resolve, reject) {
|
||
|
|
var loop = function () {
|
||
|
|
try {
|
||
|
|
Promise.resolve(anObject(call(next, iterator))).then(function (step) {
|
||
|
|
try {
|
||
|
|
if (anObject(step).done) {
|
||
|
|
noInitial ? reject($TypeError('Reduce of empty iterator with no initial value')) : resolve(accumulator);
|
||
|
|
} else {
|
||
|
|
var value = step.value;
|
||
|
|
if (noInitial) {
|
||
|
|
noInitial = false;
|
||
|
|
accumulator = value;
|
||
|
|
loop();
|
||
|
|
} else {
|
||
|
|
Promise.resolve(reducer(accumulator, value)).then(function (result) {
|
||
|
|
accumulator = result;
|
||
|
|
loop();
|
||
|
|
}, reject);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
} catch (err) { reject(err); }
|
||
|
|
}, reject);
|
||
|
|
} catch (error) { reject(error); }
|
||
|
|
};
|
||
|
|
|
||
|
|
loop();
|
||
|
|
});
|
||
|
|
}
|
||
|
|
});
|