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denoland-deno/js/performance.ts
2019-04-08 16:22:40 -04:00

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870 B
TypeScript

// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
import * as msg from "gen/cli/msg_generated";
import { sendSync } from "./dispatch";
import * as flatbuffers from "./flatbuffers";
import { assert } from "./util";
export class Performance {
/** Returns a current time from Deno's start.
* In milliseconds. Flag --allow-high-precision give
* a precise measure.
*
* const t = performance.now();
* console.log(`${t} ms since start!`);
*/
now(): number {
const builder = flatbuffers.createBuilder();
const inner = msg.Now.createNow(builder);
const baseRes = sendSync(builder, msg.Any.Now, inner)!;
assert(msg.Any.NowRes === baseRes.innerType());
const res = new msg.NowRes();
assert(baseRes.inner(res) != null);
return res.seconds().toFloat64() * 1e3 + res.subsecNanos() / 1e6;
}
}