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denoland-deno/js/performance.ts
Ryan Dahl d43b43ca78
Refactor snapshot build (#2825)
Instead of using core/snapshot_creator.rs, instead two crates are
introduced which allow building the snapshot during build.rs.

Rollup is removed and replaced with our own bundler. This removes
the Node build dependency. Modules in //js now use Deno-style imports
with file extensions, rather than Node style extensionless imports.

This improves incremental build time when changes are made to //js files
by about 40 seconds.
2019-09-02 17:07:11 -04:00

22 lines
623 B
TypeScript

// Copyright 2018-2019 the Deno authors. All rights reserved. MIT license.
import * as dispatch from "./dispatch.ts";
import { sendSync } from "./dispatch_json.ts";
interface NowResponse {
seconds: number;
subsecNanos: number;
}
export class Performance {
/** Returns a current time from Deno's start in milliseconds.
*
* Use the flag --allow-hrtime return a precise value.
*
* const t = performance.now();
* console.log(`${t} ms since start!`);
*/
now(): number {
const res = sendSync(dispatch.OP_NOW) as NowResponse;
return res.seconds * 1e3 + res.subsecNanos / 1e6;
}
}