blob: 38ffb3fbf3682b5b434bc3c449cf17e79006b7f6 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
|
'use strict';
// https://github.com/tc39/proposal-iterator-helpers
var $ = require('../internals/export');
var aFunction = require('../internals/a-function');
var anObject = require('../internals/an-object');
var getIteratorMethod = require('../internals/get-iterator-method');
var createIteratorProxy = require('../internals/iterator-create-proxy');
var iteratorClose = require('../internals/iterator-close');
var IteratorProxy = createIteratorProxy(function (arg) {
var iterator = this.iterator;
var mapper = this.mapper;
var result, mapped, iteratorMethod, innerIterator;
while (true) {
try {
if (innerIterator = this.innerIterator) {
result = anObject(this.innerNext.call(innerIterator));
if (!result.done) return result.value;
this.innerIterator = this.innerNext = null;
}
result = anObject(this.next.call(iterator, arg));
if (this.done = !!result.done) return;
mapped = mapper(result.value);
iteratorMethod = getIteratorMethod(mapped);
if (iteratorMethod === undefined) {
throw TypeError('.flatMap callback should return an iterable object');
}
this.innerIterator = innerIterator = anObject(iteratorMethod.call(mapped));
this.innerNext = aFunction(innerIterator.next);
} catch (error) {
iteratorClose(iterator);
throw error;
}
}
});
$({ target: 'Iterator', proto: true, real: true }, {
flatMap: function flatMap(mapper) {
return new IteratorProxy({
iterator: anObject(this),
mapper: aFunction(mapper),
innerIterator: null,
innerNext: null
});
}
});
|
