fix(bench): update now() to only OPTIONALLY use bigint timestamps

thi-ng · Dec 21, 2019 · 7ac391b · 7ac391b
1 parent aa4faed
commit 7ac391b
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Showing 4 changed files with 32 additions and 25 deletions.
diff --git a/packages/bench/README.md b/packages/bench/README.md
@@ -11,7 +11,6 @@ This project is part of the
 
 - [About](#about)
   - [Status](#status)
-  - [Breaking changes](#breaking-changes)
 - [Installation](#installation)
 - [Dependencies](#dependencies)
 - [Usage examples](#usage-examples)
@@ -24,19 +23,18 @@ This project is part of the
 
 Benchmarking utilities w/ optional statistics.
 
+Though no public API change (only additions), since v2.0.0 this library
+internally attempts to use high-res ES
+[`BigInt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt)
+timestamps (in Node via
+[`process.hrtime.bigint()`](https://nodejs.org/dist/latest-v12.x/docs/api/process.html#process_process_hrtime_bigint)).
+If `BigInt` is not available in the target environment, timestamps are
+still only sourced via `Date.now()`.
+
 ### Status
 
 **STABLE** - used in production
 
-### Breaking changes
-
-Though no public API change, since v2.0.0 this library internally uses
-ES
-[`BigInt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt)
-timestamps (in Node via `process.hrtime.bigint()`). See
-[caniuse](https://caniuse.com/#feat=mdn-javascript_builtins_bigint) for
-browser support.
-
 ## Installation
 
 ```bash

diff --git a/packages/bench/README.tpl.md b/packages/bench/README.tpl.md
@@ -13,16 +13,15 @@ This project is part of the
 
 ${pkg.description}
 
-${status}
-
-### Breaking changes
-
-Though no public API change, since v2.0.0 this library internally uses
-ES
+Though no public API change (only additions), since v2.0.0 this library
+internally attempts to use high-res ES
 [`BigInt`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt)
-timestamps (in Node via `process.hrtime.bigint()`). See
-[caniuse](https://caniuse.com/#feat=mdn-javascript_builtins_bigint) for
-browser support.
+timestamps (in Node via
+[`process.hrtime.bigint()`](https://nodejs.org/dist/latest-v12.x/docs/api/process.html#process_process_hrtime_bigint)).
+If `BigInt` is not available in the target environment, timestamps are
+still only sourced via `Date.now()`.
+
+${status}
 
 ${supportPackages}
 

diff --git a/packages/bench/src/now.ts b/packages/bench/src/now.ts
@@ -1,11 +1,15 @@
+let M: bigint;
+
 /**
  * If available, returns wrapper for `process.hrtime.bigint()` else
  * falls back to `Date.now()` (scaled to nanoseconds). In all cases,
  * returns a `bigint` timestamp.
  */
 export const now =
-    typeof process !== "undefined" &&
-    typeof process.hrtime !== "undefined" &&
-    typeof process.hrtime.bigint === "function"
-        ? () => process.hrtime.bigint()
-        : () => BigInt(Date.now()) * 1_000_000n;
+    typeof BigInt !== "undefined"
+        ? typeof process !== "undefined" &&
+          typeof process.hrtime !== "undefined" &&
+          typeof process.hrtime.bigint === "function"
+            ? () => process.hrtime.bigint()
+            : ((M = BigInt(1_000_000)), () => BigInt(Date.now()) * M)
+        : () => Date.now();
diff --git a/packages/bench/src/timed.ts b/packages/bench/src/timed.ts
@@ -24,5 +24,11 @@ export const timed = <T>(fn: () => T, prefix = "") => {
 export const timedResult = <T>(fn: () => T): TimingResult<T> => {
     const t0 = now();
     const res = fn();
-    return [res, Number(now() - t0) * 1e-6];
+    const t1 = now();
+    return [
+        res,
+        typeof BigInt !== "undefined"
+            ? Number(<bigint>t1 - <bigint>t0) * 1e-6
+            : <number>t1 - <number>t0
+    ];
 };