@@ -36,6 +36,7 @@ function from(Readable, iterable, opts) { |
36 | 36 | throw new ERR_INVALID_ARG_TYPE('iterable', ['Iterable'], iterable); |
37 | 37 | } |
38 | 38 |
|
| 39 | + |
39 | 40 | const readable = new Readable({ |
40 | 41 | objectMode: true, |
41 | 42 | highWaterMark: 1, |
@@ -46,11 +47,19 @@ function from(Readable, iterable, opts) { |
46 | 47 | // Flag to protect against _read |
47 | 48 | // being called before last iteration completion. |
48 | 49 | let reading = false; |
| 50 | + let isAsyncValues = false; |
49 | 51 |
|
50 | 52 | readable._read = function() { |
51 | 53 | if (!reading) { |
52 | 54 | reading = true; |
53 | | - next(); |
| 55 | + |
| 56 | + if (isAsync) { |
| 57 | + nextAsync(); |
| 58 | + } else if (isAsyncValues) { |
| 59 | + nextSyncWithAsyncValues(); |
| 60 | + } else { |
| 61 | + nextSyncWithSyncValues(); |
| 62 | + } |
54 | 63 | } |
55 | 64 | }; |
56 | 65 |
|
@@ -78,29 +87,115 @@ function from(Readable, iterable, opts) { |
78 | 87 | } |
79 | 88 | } |
80 | 89 |
|
81 | | - async function next() { |
| 90 | + // There are a lot of duplication here, it's done on purpose for performance |
| 91 | + // reasons - avoid await when not needed. |
| 92 | + |
| 93 | + function nextSyncWithSyncValues() { |
| 94 | + for (;;) { |
| 95 | + try { |
| 96 | + const { value, done } = iterator.next(); |
| 97 | + |
| 98 | + if (done) { |
| 99 | + readable.push(null); |
| 100 | + return; |
| 101 | + } |
| 102 | + |
| 103 | + if (value && |
| 104 | + typeof value.then === 'function') { |
| 105 | + return changeToAsyncValues(value); |
| 106 | + } |
| 107 | + |
| 108 | + if (value === null) { |
| 109 | + reading = false; |
| 110 | + throw new ERR_STREAM_NULL_VALUES(); |
| 111 | + } |
| 112 | + |
| 113 | + if (readable.push(value)) { |
| 114 | + continue; |
| 115 | + } |
| 116 | + |
| 117 | + reading = false; |
| 118 | + } catch (err) { |
| 119 | + readable.destroy(err); |
| 120 | + } |
| 121 | + break; |
| 122 | + } |
| 123 | + } |
| 124 | + |
| 125 | + async function changeToAsyncValues(value) { |
| 126 | + isAsyncValues = true; |
| 127 | + |
| 128 | + try { |
| 129 | + const res = await value; |
| 130 | + |
| 131 | + if (res === null) { |
| 132 | + reading = false; |
| 133 | + throw new ERR_STREAM_NULL_VALUES(); |
| 134 | + } |
| 135 | + |
| 136 | + if (readable.push(res)) { |
| 137 | + nextSyncWithAsyncValues(); |
| 138 | + return; |
| 139 | + } |
| 140 | + |
| 141 | + reading = false; |
| 142 | + } catch (err) { |
| 143 | + readable.destroy(err); |
| 144 | + } |
| 145 | + } |
| 146 | + |
| 147 | + async function nextSyncWithAsyncValues() { |
82 | 148 | for (;;) { |
83 | 149 | try { |
84 | | - const { value, done } = isAsync ? |
85 | | - await iterator.next() : |
86 | | - iterator.next(); |
| 150 | + const { value, done } = iterator.next(); |
87 | 151 |
|
88 | 152 | if (done) { |
89 | 153 | readable.push(null); |
90 | | - } else { |
91 | | - const res = (value && |
92 | | - typeof value.then === 'function') ? |
93 | | - await value : |
94 | | - value; |
95 | | - if (res === null) { |
96 | | - reading = false; |
97 | | - throw new ERR_STREAM_NULL_VALUES(); |
98 | | - } else if (readable.push(res)) { |
99 | | - continue; |
100 | | - } else { |
101 | | - reading = false; |
102 | | - } |
| 154 | + return; |
| 155 | + } |
| 156 | + |
| 157 | + const res = (value && |
| 158 | + typeof value.then === 'function') ? |
| 159 | + await value : |
| 160 | + value; |
| 161 | + |
| 162 | + if (res === null) { |
| 163 | + reading = false; |
| 164 | + throw new ERR_STREAM_NULL_VALUES(); |
103 | 165 | } |
| 166 | + |
| 167 | + if (readable.push(res)) { |
| 168 | + continue; |
| 169 | + } |
| 170 | + |
| 171 | + reading = false; |
| 172 | + } catch (err) { |
| 173 | + readable.destroy(err); |
| 174 | + } |
| 175 | + break; |
| 176 | + } |
| 177 | + } |
| 178 | + |
| 179 | + async function nextAsync() { |
| 180 | + for (;;) { |
| 181 | + try { |
| 182 | + const { value, done } = await iterator.next(); |
| 183 | + |
| 184 | + if (done) { |
| 185 | + readable.push(null); |
| 186 | + return; |
| 187 | + } |
| 188 | + |
| 189 | + if (value === null) { |
| 190 | + reading = false; |
| 191 | + throw new ERR_STREAM_NULL_VALUES(); |
| 192 | + } |
| 193 | + |
| 194 | + if (readable.push(value)) { |
| 195 | + continue; |
| 196 | + } |
| 197 | + |
| 198 | + reading = false; |
104 | 199 | } catch (err) { |
105 | 200 | readable.destroy(err); |
106 | 201 | } |
|