core: faster saveTrace by streaming 500 events at a time #5387
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patrickhulce
approved these changes
May 30, 2018
lighthouse-core/lib/asset-saver.js
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| for (const event of eventsIterator) { | ||
| yield `,\n ${JSON.stringify(event)}`; | ||
| eventsJSON += `,\n ${JSON.stringify(event)}`; | ||
| if (--eventsRemaining === 0) { |
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inline --x === always makes me think too much, WDYT about a separate statement :)
brendankenny
approved these changes
May 31, 2018
| * very large traces. | ||
| * Generates a JSON representation of traceData line-by-line to avoid OOM due to very large traces. | ||
| * COMPAT: As of Node 9, JSON.parse/stringify can handle 256MB+ strings. Once we drop support for | ||
| * Node 8, we can 'revert' PR #2593. See https://stackoverflow.com/a/47781288/89484 |
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Once we drop support for Node 8, we can 'revert' PR #2593
not sure if we actually want to anymore...we like the event-per-line formatting, right?
(We could consider shipping the pretty-json-stringify we just used in the snyk snapshot thing—no dependencies and 2.43KB before minification!—but it looks like using it on large traces will depend on Node 9 as well)
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asset-saver-test.js goes from 12.5s to 7.9s.
cc #2593 #1685